WO2022260044A1 - Alloy material, alloy product using alloy material, and machine device provided with alloy product - Google Patents

Alloy material, alloy product using alloy material, and machine device provided with alloy product Download PDF

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Publication number
WO2022260044A1
WO2022260044A1 PCT/JP2022/022984 JP2022022984W WO2022260044A1 WO 2022260044 A1 WO2022260044 A1 WO 2022260044A1 JP 2022022984 W JP2022022984 W JP 2022022984W WO 2022260044 A1 WO2022260044 A1 WO 2022260044A1
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alloy
atomic
less
range
alloy material
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PCT/JP2022/022984
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French (fr)
Japanese (ja)
Inventor
達哉 木村
浩史 白鳥
孝介 桑原
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日立金属株式会社
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Priority to EP22820223.0A priority Critical patent/EP4353859A1/en
Priority to CN202280040227.1A priority patent/CN117425742A/en
Priority to JP2023505975A priority patent/JP7327704B2/en
Publication of WO2022260044A1 publication Critical patent/WO2022260044A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y70/00—Materials specially adapted for additive manufacturing
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C30/00—Alloys containing less than 50% by weight of each constituent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
    • B22F10/20—Direct sintering or melting
    • B22F10/28—Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/0433—Nickel- or cobalt-based alloys

Definitions

  • the present invention relates to an alloy material called a high-entropy alloy, an alloy product using the alloy material, and a mechanical device comprising the alloy product.
  • HSA high-entropy alloys
  • MPEA multi-major element alloys
  • HEA and MPEA are defined as alloys composed of at least four major metal elements (each of which does not make up the majority, for example, in the range of 5 atomic % to 35 atomic %).
  • major metal elements each of which does not make up the majority, for example, in the range of 5 atomic % to 35 atomic %).
  • For HEA and MPEA for example, (a) stabilization of the mixed state due to a negative increase in the mixing entropy term in the Gibbs free energy equation, (b) delay of diffusion due to a complex fine structure, and (c) It is known that characteristics such as improvement in mechanical properties due to high lattice strain due to the difference in size of constituent atoms, and (d) improvement in heat resistance due to the combined effect (also called cocktail effect) due to the coexistence of multiple elements are known to occur. ing.
  • Patent Document 1 discloses an alloy member using a high-entropy alloy, which includes Co (cobalt), Ni (nickel), Cr (chromium), Each element of Fe (iron) and Ti (titanium) is contained in a range of 5 atomic % or more and 35 atomic % or less, and Mo (molybdenum) is contained in a range of more than 0 atomic % and 8 atomic % or less, and the balance is inevitable
  • An alloy member is described in which extremely small particles having an average particle size of 40 nm or less are dispersed and precipitated in the matrix crystals. According to Patent Document 1, it is possible to use a high-entropy alloy with high mechanical strength and provide an alloy member that is excellent in homogeneity of the alloy composition and microstructure, and excellent in shape controllability.
  • Patent Document 2 discloses an alloy material using a high entropy alloy, which contains each element of Co, Cr, Fe, Ni, and Ti in a range of 5 atomic % or more and 35 atomic % or less, and Mo Contains elements in the range of more than 0 atomic% and less than 8 atomic% and having an atomic radius larger than the atomic radii of Co, Cr, Fe and Ni in the range of more than 0 atomic% and 4 atomic% or less, and the balance is described as an alloy material consisting of unavoidable impurities.
  • the alloy product can be made into a high mechanical It is said that it is possible to provide an alloy material that exhibits excellent properties.
  • alloy products using conventional high-entropy alloys described in Patent Documents 1 and 2, etc. very small particles are dispersed and precipitated in the matrix crystal grains, and the mechanical properties of the alloy products are different from other Ni It is said to have superior properties equal to or better than base alloys and stainless steel.
  • alloy products using these alloy materials tend to deteriorate in mechanical properties (eg, tensile strength, elongation at break, etc.) in a high temperature environment of, for example, about 700°C.
  • the environmental temperature is, for example, 700.
  • the breaking elongation is low in a high temperature environment of about °C.
  • an object of the present invention is to provide an alloy material capable of improving mechanical properties in a high-temperature environment, an alloy product using the alloy material, and a mechanical device provided with the alloy product.
  • One embodiment of the present invention contains Co, Cr, Fe, and Ni each in a range of 5 atomic % or more and 40 atomic % or less, Mo in a range of more than 0 atomic % and 8 atomic % or less, and Ti. 1 atomic% or more and 10 atomic% or less, contains B in a range of more than 0 atomic% and less than 0.15 atomic%, contains or does not contain at least one of Ta and Nb in 4 atomic% or less, and the balance is The alloy material is characterized by containing unavoidable impurities.
  • B is contained in the range of 0.03 atomic % or more and 0.12 atomic % or less.
  • (ii) contains at least one of Ta and Nb at 4 atomic % or less;
  • the total content of Ti and at least one of Ta and Nb is 3 atomic % or more and 10 atomic % or less.
  • Another aspect of the present invention is an alloy product using the above alloy material, An alloy product characterized in that extremely small particles having an average particle size of 130 nm or less are dispersed and precipitated in the parent phase crystal grains of the alloy product.
  • Yet another aspect of the present invention is a mechanical device comprising the alloy product described above.
  • This specification includes the disclosure of Japanese Patent Application No. 2021-096053, which is the basis of priority of this application.
  • the present invention it is possible to improve the mechanical properties of an alloy material, an alloy product using the alloy material, and a mechanical device provided with the alloy product in a high-temperature environment.
  • FIG. 2 is a secondary electron image obtained by SEM observation of a treated cross section of a cut piece of alloy workpiece W1. It is a secondary electron image obtained by SEM observation of the treated cross section of the cut piece of the alloy workpiece W3. It is an electron diffraction pattern of the mother phase crystal grains obtained by STEM observation. 2 is a dark-field image (DF-STEM) of matrix phase crystal grains obtained by STEM observation. 4 is an image showing the results of elemental mapping of extremely small particles in the matrix crystal grains by Energy Dispersive X-ray Spectroscopy (EDX).
  • EDX Energy Dispersive X-ray Spectroscopy
  • FIG. 2 is an image showing a BO 2 ⁇ ion intensity distribution obtained by qualitative evaluation of elemental distribution by SIMS (Secondary Ion Mass Spectroscopy).
  • FIG. 6 is a graph showing the BO 2 ⁇ ion intensity distribution at each position along the arrow inserted in the BO 2 ⁇ ion intensity distribution of each figure in FIG. 5;
  • the inventors examined various applications based on conventional alloy materials. As a result, it was confirmed that the mechanical properties of the alloy products deteriorated as the environmental temperature increased. As a result of various investigations and considerations on the cause, it was thought that this phenomenon is affected by the decrease in the strength of the grain boundary, which is the starting point of fracture, as the environmental temperature rises. In addition, the inventors have come up with the idea that the specific composition can improve the strength of the grain boundary and improve the mechanical properties of the alloy product in a high-temperature environment. The present invention is made based on these findings.
  • the alloy product has high mechanical properties even in a high temperature environment (for example, 700 ° C.). It is desirable to improve the strength of grain boundaries.
  • the present inventors diligently studied changes in the metal structure when different elements were added and changes in the mechanical properties of the alloy product in a high-temperature environment. As a result, it was found that the strength of grain boundaries can be improved by containing B (boron) in an appropriate range. As a result, the mechanical properties (eg, tensile strength, elongation at break, etc.) under high-temperature environments could be improved.
  • B boron
  • the alloy material according to the embodiment contains Co, Cr, Fe, and Ni in a range of 5 atomic % or more and 40 atomic % or less, Mo in a range of more than 0 atomic % and 8 atomic % or less, and 1 atom of Ti. % or more and 10 atomic % or less, contains B in a range of more than 0 atomic % and less than 0.15 atomic %, contains or does not contain at least one of Ta and Nb at 4 atomic % or less, and the balance is unavoidable Consists of impurities.
  • Co, Cr, Fe, and Ni are basically the main component elements that constitute the parent phase crystal grains of the alloy material or alloy product, and are believed to contribute to the improvement of corrosion resistance due to the cocktail effect.
  • the contents of these component elements in the alloy material will be specifically described below.
  • the upper limit and lower limit of the component elements described below can be combined arbitrarily.
  • the preferred range, the more preferred range, and the further preferred range can be combined as appropriate.
  • the Co content is preferably 20 atomic % or more and 40 atomic % or less, more preferably 25 atomic % or more and 38 atomic % or less, and even more preferably 30 atomic % or more and 36 atomic % or less.
  • the Cr content is preferably 10 atomic % or more and 25 atomic % or less, more preferably 16 atomic % or more and 23 atomic % or less, and further preferably 18 atomic % or more and 21 atomic % or less.
  • the Fe content is preferably 10 atomic % or more and 25 atomic % or less, more preferably 12 atomic % or more and 20 atomic % or less, and even more preferably 14 atomic % or more and 17 atomic % or less.
  • the Ni content is preferably 15 atomic % or more and 30 atomic % or less, more preferably 17 atomic % or more and 28 atomic % or less, and still more preferably 21 atomic % or more and 26 atomic % or less.
  • Mo contributes to the improvement of corrosion resistance together with Cr.
  • the content of Mo in the alloy material is more preferably 1 atomic % or more and 7 atomic % or less, and further preferably 2 atomic % or more and 5 atomic % or less.
  • Ti is a component that constitutes microscopic particles dispersed and precipitated in the matrix crystal grains, and is considered to contribute to the strength improvement of the alloy material.
  • the Ti content in the alloy material is preferably 1 atomic % or more and 10 atomic % or less, preferably 1 atomic % or more and 9 atomic % or less, more preferably 2 atomic % or more and 9 atomic % or less.
  • Atomic % or more and 7 atomic % or less are more preferable. 2 atomic % or more and 5 atomic % or less is even more preferable.
  • B boron
  • the mechanical properties of the alloy product can be improved in a high temperature environment.
  • the B content is less than 0.15 atomic %, it is possible to suppress the formation of coarse precipitates in the alloy product, and the mechanical properties of the alloy product in a room temperature environment can be improved. Decrease can be suppressed.
  • the alloy material can further contain at least one of Ta and Nb.
  • Ta and Nb By adding at least one of Ta and Nb having a large atomic size, the mechanical properties of the alloy product using the alloy material can be further improved by solid-solution strengthening. Furthermore, it has the effect of strengthening the passive film of the alloy material and improving the pitting corrosion resistance.
  • Ta and Nb like Ti, are components that form a predetermined intermetallic compound phase, precipitation of the intermetallic compound phase is controlled by setting the total amount of Ta, Nb, and Ti to a predetermined value or less.
  • the alloy material contains at least one of Ta and Nb
  • the content of at least one of Ta and Nb (when both Ta and Nb are included, the total content of Ta and Nb) is It is preferable to make the range greater than 0 atomic % and 4 atomic % or less.
  • the range of 0.5 atomic % or more and 3 atomic % or less is more preferable, and the range of 1 atomic % or more and 2.5 atomic % or less is even more preferable.
  • the alloy material contains at least one of Ta and Nb at 4 atomic % or less, Ti and , Ta and Nb in a total amount of 3 atomic % or more and 10 atomic % or less.
  • those further containing at least one of Ta and Nb are preferable. This is because by further including Ta, the passivation film of CrMo can be strengthened, and the effect of improving the corrosion resistance of the alloy can be obtained.
  • the alloy material contains, as main components, Co in the range of 25 atomic % to 38 atomic %, Cr in the range of 16 atomic % to 23 atomic %, and Fe in the range of 12 atomic % to 20 atomic %. It contains the Ni in the range of 17 atomic % or more and 28 atomic % or less, contains the Mo in the range of 1 atomic % or more and 7 atomic % or less, and contains the Ti in the range of 2 atomic % or more and 9 atomic % as an auxiliary component. It is more preferable to contain in the range of atomic % or less.
  • “Inevitable impurities” refer to component elements that are difficult to remove completely, but that should be reduced as much as possible.
  • unavoidable impurities include Si (silicon), P (phosphorus), S (sulfur), N (nitrogen), O (oxygen), and the like.
  • the total content of unavoidable impurities contained in the alloy material is preferably 1% by mass or less. In other words, the total content of the constituent elements intentionally contained in the alloy material is preferably 99% by mass or more. The content of unavoidable impurities contained in the alloy material will be described in more detail below.
  • the Si content is preferably 0.2% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less.
  • the P content is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.02% by mass or less.
  • the S content is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.02% by mass or less.
  • the N content is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.02% by mass or less.
  • the O content is preferably 0.2% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less.
  • the alloy product according to the embodiment is an alloy product using the alloy material according to the above embodiment, and has a microstructure containing parent phase crystal grains.
  • the alloy product since the alloy material contains B, the strength of the grain boundaries can be improved. Therefore, it is an alloy product with improved mechanical properties in a high-temperature environment.
  • microstructure of the alloy product is not particularly limited as long as it contains mother phase crystal grains, but it is preferable to have microscopic particles dispersed and precipitated in the mother phase crystal grains. This is because the mechanical properties and the like are further improved. In the case of alloy products produced by additive manufacturing, there is a feature that very small particles tend to precipitate.
  • the ultra-small particles are crystalline particles of the L12 type ordered phase in which a predetermined component element is concentrated more than other parts in the mother phase crystal grains. Concentrated crystalline particles.
  • the average particle size of the ultra-small particles is, for example, preferably 130 nm or less, more preferably 10 nm or more and 130 nm or less, and even more preferably 20 nm or more and 100 nm or less. This is because the mechanical properties and the like are further improved when the average particle size of the extremely small particles is within these ranges.
  • the average particle diameter of the extremely small particles is, for example, a dark field image (DF-STEM) of the mother phase crystal grains obtained by STEM observation, and the maximum diameter (maximum length) is at least 5 nm or more. After selecting one microparticle, the maximum diameter (maximum length) of at least five microparticles is measured, and the average of the maximum diameters is obtained.
  • the parent phase crystal grains are not particularly limited, for example, those having a face-centered cubic (FCC) crystal structure and an average crystal grain size of 300 ⁇ m or less are preferable. This is because face-centered cubic crystals are one type of close-packed structure, and mechanical properties and the like are improved when the mother phase crystal grains have a face-centered cubic crystal structure.
  • the average crystal grain size is 300 ⁇ m or less, mechanical properties, corrosion resistance, etc. are improved.
  • the average crystal grain size is more preferably 200 ⁇ m or less, and even more preferably 150 ⁇ m or less. This is because the mechanical properties, corrosion resistance, etc. are further improved.
  • the matrix crystal grains may have a simple cubic (SC) crystal structure in addition to the face-centered cubic crystal structure.
  • the alloy product according to the embodiment is preferably a member that requires high mechanical properties in a high temperature environment because it can improve the mechanical properties in a high temperature environment.
  • Such members include, for example, turbine members including turbine blades, boiler members, engine members, nozzle members, casings, pipes, valves and the like, structural members for plants, structural members for generators, Structural members for nuclear reactors, structural members for aerospace, members for hydraulic equipment, bearings, pistons, gears, mechanical members for various devices such as rotating shafts, and the like are preferred.
  • the alloy product may be, for example, another member such as an impeller.
  • a mechanical device that requires high mechanical properties in a high-temperature environment is preferable because it can improve the mechanical properties in a high-temperature environment.
  • Preferred examples of such mechanical devices include turbines, boilers, engines, nozzles, plants, generators, nuclear reactors, aerospace devices, hydraulic devices, power transmission devices, and other various devices.
  • FIG. 1 is a schematic process diagram showing an example of a method for manufacturing an alloy product according to an embodiment.
  • the method for manufacturing an alloy product according to the embodiment generally includes at least an alloy material preparation step S1 and a forming step S2, and performs a quasi-solution heat treatment according to the forming process. It further includes step S3 or sintering step S4.
  • the method for manufacturing an alloy product according to the embodiment can also include an aging heat treatment step S5 when further including the quasi-solution heat treatment step S3 as in the example shown in FIG. Each step will be described in more detail below.
  • alloy material producing step S1 an alloy material that will be the material of the alloy product is produced.
  • alloy material production step S1 there is no particular limitation on the detailed procedure as long as an alloy material capable of producing a desired alloy product is obtained.
  • This process includes a raw material mixing and melting step S1a for obtaining molten metal, and an alloy solidification step S1b for obtaining an alloy material by solidifying the molten metal.
  • the raw material mixing and melting step S1a is not particularly limited as long as the raw material metal is mixed and melted to obtain a molten metal. ), a melting step of mixing raw metals and once melting to obtain a molten metal, an alloy ingot forming step of once solidifying the molten metal to form an alloy ingot for remelting, and remelting the alloy ingot for remelting and a remelting step of obtaining a cleaned molten metal.
  • the remelting method is not particularly limited as long as the cleanliness of the alloy can be improved, but for example, vacuum arc remelting (VAR) is preferred.
  • the method of solidifying the molten metal in the alloy solidification step S1b is not particularly limited as long as the alloy material is obtained in a form suitable for use in the forming step S2 (for example, an alloy lump (ingot), alloy powder, etc.).
  • a method of obtaining an alloy ingot as an alloy material by solidifying the molten metal by a casting method, a method of obtaining an alloy powder as an alloy material by scattering and solidifying the molten metal by an atomizing method, and the like are preferable.
  • the average particle size of the alloy powder is preferably in the range of 5 ⁇ m to 200 ⁇ m, more preferably in the range of 10 ⁇ m to 100 ⁇ m, and even more preferably in the range of 10 ⁇ m to 50 ⁇ m.
  • a classification step of classifying the average particle size of the alloy powder into a range of 5 ⁇ m or more and 200 ⁇ m or less may be further performed after the alloy powder is obtained by the atomization method.
  • the classification step is not an essential step, it is preferably performed from the viewpoint of improving the usability of the alloy powder.
  • the classification step is not an essential step, it is preferably performed from the viewpoint of improving the usability of the alloy powder.
  • a formed body having a desired shape is formed from the alloy material obtained in the alloy material producing step S1. Note that.
  • the method for manufacturing an alloy product according to the embodiment may be one in which the molded body formed in the forming step S2 is directly manufactured as an alloy product.
  • the method for forming a molded body from an alloy material is not particularly limited as long as a molded body having a desired shape can be formed, and varies depending on the type of alloy material.
  • a method of molding cutting, plastic working (e.g., forging, drawing, rolling, etc.), machining (e.g., punching, cutting, etc.), etc. are performed to make the alloy processed body into a molded body.
  • a molding method may also be used.
  • the preferred method for forming a compact from the alloy material is, for example, an additive manufacturing process, a powder metallurgy process, or the like.
  • the layered manufacturing process is not particularly limited, and conventional processes can be used as appropriate.
  • AM additive manufacturing
  • melting and solidification instead of sintering, local melting and rapid solidification (hereinafter sometimes referred to as "melting and solidification" can be used to produce a near-net-shape alloy product.
  • Additive manufacturing processes are characterized by the ability to directly produce three-dimensional parts with complex geometries with mechanical properties comparable to or better than forgings.
  • the AM method is not particularly limited, and conventional processes can be used as appropriate. For example, Selective Laser Melting (SLM), Electron Beam Melting (EBM), Laser Metal Deposition (LMD), Directed energy deposition deposition: DED) or the like can be used.
  • SLM Selective Laser Melting
  • EBM Electron Beam Melting
  • LMD Laser Metal Deposition
  • DED Directed energy deposition deposition
  • This additive manufacturing process includes an alloy powder bed preparation step of spreading alloy powder to prepare an alloy powder bed having a predetermined thickness, and a laser beam irradiating a predetermined area of the alloy powder bed to localize the alloy powder in this area. It is a layered manufacturing process in which a layered body is formed by repeating a laser melting and solidifying process in which the material is melted and solidified rapidly.
  • the thickness h of the alloy powder bed is selected from the range of 0.02 mm or more and 0.2 mm or less so that the density and shape accuracy of the laminate-molded body are as high as possible
  • the laser light output P is selected from the range of 50 W or more and 1000 W or less
  • the laser beam scanning speed S is selected from the range of 50 mm / s or more and 10000 mm / s or less
  • the laser beam scanning interval L is selected from the range of 0.05 mm or more and 0.2 mm or less Select.
  • E P / (h ⁇ S ⁇ L)
  • the laminate-molded body produced by the laser melting and solidification process is buried in the alloy powder bed.
  • the additive manufacturing process may comprise, following the laser melting and solidification step, a removal step of removing the additively manufactured body from the alloy powder bed.
  • a removal step of removing the additively manufactured body from the alloy powder bed.
  • the method for taking out the layered product there is no particular limitation on the method for taking out the layered product, and conventional methods can be used.
  • sandblasting using alloy powder can be preferably used.
  • Sandblasting using alloy powder has the advantage that the removed alloy powder bed can be pulverized together with the blown alloy powder to be reused as alloy powder.
  • the powder metallurgy process there are no particular limitations on the powder metallurgy process, and conventional processes can be used as appropriate. Further, when the alloy material is an alloy powder, in order to improve the shape accuracy of the molded product, the molded product obtained by an additive manufacturing process, a powder metallurgy process, or the like may be further subjected to cutting, plastic working, machining, or the like.
  • a quasi-solution heat treatment is performed on a molded body (alloy processed body) molded from an alloy ingot or a molded body (laminated molded body) molded from an alloy powder by an additive manufacturing process.
  • the compact is heated and held at a predetermined temperature for a certain period of time.
  • the segregated substances remaining in the molded body and the composition distribution are homogenized, and an alloy processed product obtained from the alloy processed body or an alloy shaped product obtained from the layered structure is manufactured as an alloy product.
  • the alloy material of the present invention there is no scientifically established knowledge such as a phase equilibrium diagram at the present stage, and the temperature at which segregates are completely dissolved cannot be accurately defined. Therefore, the name of this heat treatment is called quasi-solution heat treatment.
  • the temperature of the quasi-solution heat treatment is not particularly limited, but for example, it is preferably in the range of 1000 ° C. or higher and 1250 ° C. or lower, more preferably in the range of 1050 ° C. or higher and 1200 ° C. or lower, and further preferably in the range of 1100 ° C. or higher and 1180 ° C. or lower. preferable. Sufficient homogenization is possible if the temperature of the quasi-solution heat treatment is 1000° C. or higher. Further, if the temperature of the quasi-solution heat treatment is 1250° C. or less, the matrix phase crystal grains do not coarsen, and corrosion resistance and mechanical properties are improved.
  • the atmosphere of the quasi-solution heat treatment is not particularly limited, and may be an air atmosphere or a non-oxidizing atmosphere (an atmosphere in which substantially no oxygen is present, such as a vacuum, a high-purity argon atmosphere, a high-purity nitrogen atmosphere, etc. ) can be used.
  • a non-oxidizing atmosphere an atmosphere in which substantially no oxygen is present, such as a vacuum, a high-purity argon atmosphere, a high-purity nitrogen atmosphere, etc.
  • the holding time of the quasi-solution heat treatment may be appropriately set within the range of 0.1 hours or more and 100 hours or less, taking into consideration the volume and heat capacity of the object to be heat treated, the temperature of the heat treatment, and the like.
  • the temperature range where the intermetallic compound phase easily grows (for example, the range of 800 ° C. or higher and 900 ° C. or lower) is preferably passed through as quickly as possible.
  • the molded body may be heated to maintain a predetermined temperature for a certain period of time, and then quenched by air cooling or the like.
  • a molded body (alloy processed body) molded from an alloy ingot or a molded body molded from alloy powder in a layered manufacturing process (laminated It is also possible to add an aging heat treatment step S5 in which aging heat treatment is performed on the shaped body).
  • the target of the aging heat treatment may be a molded body subjected to quasi-solution heat treatment.
  • the compact is heated and held at a predetermined temperature for a certain period of time. As a result, microparticles and other precipitates are generated or grown in the mother phase crystal grains in the compact. In this way, an alloy processed product obtained from the alloy processed product or an alloy shaped product obtained from the layered product is manufactured as an alloy product.
  • the temperature of the aging heat treatment is not particularly limited, it is preferably in the range of 500°C or higher and 900°C or lower, and more preferably in the range of 600°C or higher and 850°C or lower. If the temperature of the aging heat treatment is 500° C. or higher, the precipitates in the parent phase crystal grains in the compact are changed. Further, when the temperature of the quasi-solution heat treatment is 900° C. or less, excessive precipitates are not formed, and corrosion resistance and mechanical properties are improved.
  • the atmosphere of the quasi-solution heat treatment is not particularly limited, and may be an air atmosphere or a non-oxidizing atmosphere (an atmosphere in which substantially no oxygen is present, such as a vacuum, a high-purity argon atmosphere, a high-purity nitrogen atmosphere, etc. ) can be used.
  • the holding time of the aging heat treatment may be appropriately set in the range of 0.5 hours or more and 24 hours or less, taking into consideration the volume and heat capacity of the body to be heat treated, the temperature of the heat treatment, and the like.
  • the compact In the aging heat treatment, the compact may be heated to a predetermined temperature and held for a certain period of time, and then rapidly cooled by air cooling or the like.
  • the sintering step S4 the molded body formed by the powder metallurgy process is sintered from the alloy powder. Thereby, an alloy sintered product is produced as an alloy product.
  • the sintering method is not particularly limited, and conventional methods can be used as appropriate.
  • the sintering method may be a method in which the molding process step S2 and the sintering process S4 are performed completely independently (a method in which only molding is performed in the molding process step S2 and only sintering is performed in the sintering process S4).
  • a method such as hot isostatic pressing (HIP) or the like may be used in which the molding step S2 and the sintering step S4 are integrally performed.
  • HIP hot isostatic pressing
  • the sintering step S4 can be omitted for the laminate-molded body described above.
  • HIP on the other hand, can be implemented. HIPing can also reduce voids that may be inherent in the laminate.
  • the sintering temperature is not particularly limited, but may be, for example, in the same temperature range as in the quasi-solution heat treatment step S3. That is, the sintering temperature is, for example, preferably in the range of 1000°C to 1250°C, more preferably in the range of 1050°C to 1200°C, and even more preferably in the range of 1100°C to 1180°C.
  • the sintering process including HIP it is preferable to cool as soon as possible, such as air cooling. If a sufficient cooling rate cannot be obtained due to restrictions on equipment used in the sintering process, the quasi-solution treatment process S3 described above may be added after the sintering process, and rapid cooling may be performed by air cooling or the like.
  • the method for manufacturing an alloy product according to the embodiment includes a finishing step of performing surface finishing and the like on the alloy product obtained in the quasi-solution heat treatment step S3 or the sintering step S4. Further may be provided as necessary.
  • the alloy materials A1 and A2 are HEA alloy materials (examples) containing B (boron) within the content range according to the present invention, and the alloy material A3 contains B in accordance with the present invention.
  • the alloy material A4 is an HEA alloy material (comparative example) containing the content outside the range of B, and the alloy material A4 is an HEA alloy material (comparative example) that does not contain B.
  • each of the alloy materials A1 to A4 was machined to form the alloy processed body into a compact (10 mm ⁇ 10 mm ⁇ 40 mm rectangular parallelepiped) (forming step).
  • quasi-solution heat treatment was performed on each of the alloy processed bodies formed from the alloy materials A1 to A4 (quasi-solution heat treatment step).
  • the alloy work piece was held at 1120° C. for 1 hour in an air atmosphere and then quenched.
  • air cooling with an average cooling rate of about 10° C./s from 800° C. to 900° C. was adopted.
  • alloy workpieces W1 to W4 were produced as alloy products from the alloy materials A1 to A4, respectively.
  • the quasi-solution heat treatment step can be performed at 1000° C. to 1180° C. for 0.1 hour or more and 100 hours or less.
  • each of the obtained alloy powders was classified by a sieve to select particles having a particle size of 20 ⁇ m or more and 45 ⁇ m or less, and alloy powders P1 to P4 were produced (alloy material production step).
  • alloy powders P1 to P4 were produced (alloy material production step).
  • the average particle size of each was about 30 ⁇ m.
  • the alloy powder P1 is a B-free HEA alloy powder (comparative example) and was prepared as a reference sample.
  • the alloy powder P2 is an HEA alloy powder containing B (Example)
  • the alloy powder P3 is an HEA alloy powder containing B and Ta (Example).
  • the alloy powder P4 is an HEA alloy powder (comparative example) that does not contain B but contains Ta.
  • a trial powder with a higher Ti content of 10.7 atomic % was also produced from the composition of the alloy powder P2, but cracks occurred during the following layered manufacturing. Based on the results of this trial production, the upper limit of the Ti content was set to 10 atomic %.
  • each of the laminate-molded bodies molded from the alloy powders P1 to P4 was taken out from the alloy powder bed.
  • quasi-solution heat treatment step was performed on each of the laminate-molded bodies.
  • the laminate-molded body was held at 1120° C. for 3 hours in an air atmosphere, and then rapidly cooled.
  • air cooling with an average cooling rate of about 10° C./s from 800° C. to 900° C. was adopted.
  • alloy shaped objects M1 to M4 were produced as alloy products from the alloy powders P1 to P4, respectively.
  • the quasi-solution heat treatment step can be performed at 1000° C. to 1180° C.
  • the alloy molded article M3 obtained from the alloy powder P3 and subjected to the quasi-solution heat treatment was further subjected to aging heat treatment by holding the layered molded article at 650 ° C. for 8 hours in an air atmosphere, and then cooled in a furnace.
  • Product M5 was obtained in combination.
  • the tensile strength of 900 MPa or more was evaluated as “excellent”, the case of 800 MPa or more was evaluated as “acceptable”, and the case of less than 800 MPa was evaluated as "failed”.
  • the case of 8% or more was evaluated as “excellent”
  • the case of 7% or more was evaluated as “acceptable”
  • the case of less than 7% was evaluated as “failed”.
  • the alloy shaped products M1 to M5 are expected to have higher properties because the solidified structure is finer than that of the alloy processed product. Therefore, regarding the tensile strength, a case of 1000 MPa or more was evaluated as “acceptable”, and a case of less than that was evaluated as "failed”.
  • a case of 10% or more was defined as "accepted”, and a case of less than that was defined as "failed”.
  • the alloy workpieces W1 and W2 containing B within the content range according to the present invention have improved mechanical properties in a high-temperature environment compared to the alloy workpiece W4 that does not contain B.
  • the alloy workpiece W3 containing B outside the range of the content according to the present invention (0.15 atomic % or more) had a fracture elongation lower than those of the alloy workpieces W1 and W2.
  • the alloy shaped products M2 and M3 (examples) containing B have improved mechanical properties in a high-temperature environment compared to the alloy shaped product M1 (comparative example) that does not contain B.
  • the alloy processed products W1 to W4 and the alloy shaped products M1 to M5 were each subjected to X-ray diffraction (XRD) measurement to identify the crystal structure of the parent phase crystal grains and the precipitated phases.
  • XRD X-ray diffraction
  • the crystal structure of the parent phase crystal grains was mainly face-centered cubic (FCC) in all of the alloy workpieces W1 to W4 and the alloy shaped products M1 to M5.
  • FCC face-centered cubic
  • SC simple cubic
  • each of the alloy workpieces W1 to W4 and the alloy shaped objects M1 to M5 is cut, the cross section of the cut piece is mirror-polished, and the cross section is treated with a 10% by mass oxalic acid aqueous solution, 3V ⁇
  • An electrolytic etching treatment was performed under an electric field condition of 0.2A.
  • SEM observation was performed on the processed cross section of each cut piece. Precipitates become starting points of cracks when stress acts on the alloy product, and the larger the size of the precipitates, the more likely they are to become starting points of cracks.
  • FIG. 2A is a secondary electron image obtained by SEM observation of the treated cross section of the alloy workpiece W1.
  • FIG. 2B is a secondary electron image obtained by SEM observation of the treated cross section of the alloy workpiece W3.
  • alloy workpiece W4 and the alloy shaped articles M1 and M4 do not form precipitates, but have poor mechanical properties at high temperatures.
  • Microstructure observation 2 High-magnification observation by STEM (Scanning Transmission Electron Microscope) was performed in order to evaluate extremely small particles in the mother phase crystal grains of the alloy model M2.
  • one surface of the cut piece of the alloy model M2 obtained above was mirror-polished, and a test piece with a thickness of about 100 nm was cut from the polished surface by a microsampling method using FIB (Focused Ion Beam).
  • FIB Fluorine-Beam
  • FB-2100 model manufactured by Hitachi High-Tech Co., Ltd. was used for the microsampling method.
  • this test piece was observed by STEM. Observation conditions of STEM were as follows.
  • FIG. 3A is an electron diffraction pattern of the matrix phase crystal grains obtained by STEM observation of the alloy shaped article M2
  • FIG. 3B is a dark field image (DF- STEM).
  • FIG. 4 is an image showing the results of elemental mapping of extremely small particles in the matrix crystal grains of the alloy shaped product M2 by energy dispersive X-ray spectroscopy (EDX).
  • EDX energy dispersive X-ray spectroscopy
  • Such very small particles are believed to be the ⁇ ' phase observed in the electron diffraction pattern.
  • the ⁇ ' phase contributes to the improvement of mechanical properties by providing resistance to dislocation propagation in grains.
  • high-magnification observation by STEM confirmed a similar microstructure composed of matrix crystal grains composed of the FCC phase and extremely small grains in which Ni and Ti were concentrated.
  • one surface of the cut pieces of the alloy shaped objects M1 to M5 obtained above was mirror-polished and observed by SIMS.
  • the SIMS observation conditions were as follows.
  • Apparatus model AMETEK CAMECA secondary ion mass spectrometer model IMS-7F Primary ion conditions: Cs + , 15 kV Analysis area: 100 ⁇ m ⁇ 100 ⁇ m Secondary ion polarity: negative Detected element: B (detected as BO 2 - ion)
  • FIG . 5 is an image showing the BO 2 - ion intensity distribution obtained by SIMS observation of the alloy shaped objects M1 to M5, and FIG. It is a graph which shows distribution. Since the absolute value of the ion intensity depends on the measurement conditions of the device, etc., in this study, each sample was observed under the same measurement conditions as the above SIMS observation conditions, and the ion intensity ratio obtained at that time was used as a relative value. A qualitative evaluation was performed on
  • B contained in the corresponding raw material powders (P2 and P3) is contained in the shaped bodies, and B is obtained from the raw material powders (P1 and P4) that do not contain B. It was confirmed that B was present at a concentration 10 times higher as a whole than M1 and M4. In M3 and M5 obtained from the powder (P3) containing B and Ta, uneven distribution of B at grain boundaries was observed. Even in the powder (P4) containing only Ta and not containing B, uneven distribution of B occurred at the grain boundary, but the ionic strength ratio was low and the amount of uneven distribution was small.
  • the raw material powders (P1 and P4) containing no B have a low relative secondary ion intensity of B.

Abstract

The present invention provides: an alloy material which has improved mechanical characteristics in a high temperature environment; an alloy product which uses this alloy material; and a machine device which is provided with this alloy product.　This alloy material contains Co, Cr, Fe and Ni respectively in an amount within the range from 5% by atom to 40% by atom, Mo in an amount of more than 0% by atom but not more than 8% by atom, Ti in an amount of 1% by atom to 10% by atom, and B in an amount of more than 0% by atom but less than 0.15% by atom, with the balance being made up of unavoidable impurities. This alloy material may contain B in an amount within the range from 0.03% by atom to 0.12% by atom, and may contain at least one of Ta and Nb in an amount of 4% by atom or less. In addition, it is preferable that the sum of Ti and at least one of Ta and Nb is from 3% by atom to 10% by atom.

Description

合金材、合金材を用いた合金製造物、及び合金製造物を備える機械装置Alloy materials, alloy products using alloy materials, and machinery equipped with alloy products
　本発明は、ハイエントロピー合金と称される合金材、該合金材を用いた合金製造物、及び該合金製造物を備える機械装置に関するものである。 The present invention relates to an alloy material called a high-entropy alloy, an alloy product using the alloy material, and a mechanical device comprising the alloy product.
　近年、従来の合金（例えば、１～３種類の主要成分元素に複数種の副成分元素を微量添加した合金）の技術思想とは一線を画した新しい技術思想の合金として、ハイエントロピー合金（ＨＥＡ）や多種主要元素合金（ＭＰＥＡ）が提唱されている。 In recent years, high-entropy alloys (HEA) have been developed as alloys with new technical concepts that are distinct from conventional alloys (for example, alloys in which a small amount of multiple subcomponent elements are added to one to three main component elements). ) and multi-major element alloys (MPEA) have been proposed.
　ＨＥＡやＭＰＥＡは、少なくとも４種類の主要金属元素（それぞれが過半を占めない、例えば、５原子％以上３５原子％以下の範囲）から構成された合金と定義されている。ＨＥＡやＭＰＥＡについては、例えば、（ａ）ギブスの自由エネルギー式における混合エントロピー項が負に増大することに起因する混合状態の安定化、（ｂ）複雑な微細構造による拡散の遅延、（ｃ）構成原子のサイズ差に起因する高格子歪みに起因する機械的特性の向上、（ｄ）多種元素共存による複合影響（カクテル効果とも言う）による耐熱性の向上などの特徴が発現することが知られている。 HEA and MPEA are defined as alloys composed of at least four major metal elements (each of which does not make up the majority, for example, in the range of 5 atomic % to 35 atomic %). For HEA and MPEA, for example, (a) stabilization of the mixed state due to a negative increase in the mixing entropy term in the Gibbs free energy equation, (b) delay of diffusion due to a complex fine structure, and (c) It is known that characteristics such as improvement in mechanical properties due to high lattice strain due to the difference in size of constituent atoms, and (d) improvement in heat resistance due to the combined effect (also called cocktail effect) due to the coexistence of multiple elements are known to occur. ing.
　ＨＥＡやＭＰＥＡから構成される合金部材や合金製造物として、例えば、特許文献１には、ハイエントロピー合金を用いた合金部材であって、Ｃｏ（コバルト）、Ｎｉ（ニッケル）、Ｃｒ（クロム）、Ｆｅ（鉄）、及びＴｉ（チタン）の各元素をそれぞれ５原子％以上３５原子％以下の範囲で含み、かつＭｏ（モリブデン）を０原子％超８原子％以下の範囲で含み、残部が不可避的不純物からなり、母相結晶中に平均粒径４０ｎｍ以下の極小粒子が分散析出している合金部材が記載されている。特許文献１によれば、高機械的強度を有するハイエントロピー合金を用い、合金組成及び微細組織の均質性に優れ、かつ形状制御性に優れた合金部材を提供できるとされている。 As alloy members and alloy products composed of HEA and MPEA, for example, Patent Document 1 discloses an alloy member using a high-entropy alloy, which includes Co (cobalt), Ni (nickel), Cr (chromium), Each element of Fe (iron) and Ti (titanium) is contained in a range of 5 atomic % or more and 35 atomic % or less, and Mo (molybdenum) is contained in a range of more than 0 atomic % and 8 atomic % or less, and the balance is inevitable An alloy member is described in which extremely small particles having an average particle size of 40 nm or less are dispersed and precipitated in the matrix crystals. According to Patent Document 1, it is possible to use a high-entropy alloy with high mechanical strength and provide an alloy member that is excellent in homogeneity of the alloy composition and microstructure, and excellent in shape controllability.
　また、特許文献２には、ハイエントロピー合金を用いた合金材であって、Ｃｏ、Ｃｒ、Ｆｅ、Ｎｉ、及びＴｉの各元素をそれぞれ５原子％以上３５原子％以下の範囲で含み、Ｍｏを０原子％超８原子％未満の範囲で含み、かつＣｏ、Ｃｒ、Ｆｅ及びＮｉの原子半径に比してより大きい原子半径を有する元素を０原子％超４原子％以下の範囲で含み、残部が不可避的不純物からなる合金材が記載されている。特許文献２によれば、特許文献１の合金をベースとし、より大きい原子半径を有する元素としてＴａ、Ｎｂ、Ｈｆ、Ｚｒ及びＹのうちの一種以上を添加することによって、合金製造物が高い機械的特性を示す合金材を提供できるとされている。 Further, Patent Document 2 discloses an alloy material using a high entropy alloy, which contains each element of Co, Cr, Fe, Ni, and Ti in a range of 5 atomic % or more and 35 atomic % or less, and Mo Contains elements in the range of more than 0 atomic% and less than 8 atomic% and having an atomic radius larger than the atomic radii of Co, Cr, Fe and Ni in the range of more than 0 atomic% and 4 atomic% or less, and the balance is described as an alloy material consisting of unavoidable impurities. According to WO 2005/013000, by using the alloy of WO 2005/010110 as a base and adding one or more of Ta, Nb, Hf, Zr and Y as elements with larger atomic radii, the alloy product can be made into a high mechanical It is said that it is possible to provide an alloy material that exhibits excellent properties.
国際公開第２０１７／１３８１９１号WO2017/138191 国際公開第２０１９／０８８１５７号WO2019/088157
　特許文献１や特許文献２などに記載された従来のハイエントロピー合金を用いた合金材は、母相結晶粒中に極小粒子が分散析出しており、合金製造物の機械的特性に関して他のＮｉ基合金やステンレス鋼などと同等以上に優れた特性を有するとされている。しかしながら、それらの合金材を用いた合金製造物は、例えば、７００℃程度の高温環境下における機械的特性（例えば、引張強度、破断伸び等）が低下する傾向がある。中でも、従来のハイエントロピー合金を用いた合金粉末（合金材）から積層造形プロセスで成形された積層造形体に対して擬溶体化熱処理が行われた合金造形物では、環境温度が、例えば、７００℃程度の高温環境下において、破断伸びが低いと言う課題がある。 In the alloy materials using conventional high-entropy alloys described in Patent Documents 1 and 2, etc., very small particles are dispersed and precipitated in the matrix crystal grains, and the mechanical properties of the alloy products are different from other Ni It is said to have superior properties equal to or better than base alloys and stainless steel. However, alloy products using these alloy materials tend to deteriorate in mechanical properties (eg, tensile strength, elongation at break, etc.) in a high temperature environment of, for example, about 700°C. Among them, in an alloy modeled product in which a quasi-solution heat treatment is performed on a layered product formed by a layered manufacturing process from an alloy powder (alloy material) using a conventional high-entropy alloy, the environmental temperature is, for example, 700. There is a problem that the breaking elongation is low in a high temperature environment of about °C.
　したがって、本発明の目的は、高温環境下における機械的特性を向上できる合金材、合金材を用いた合金製造物、及び合金製造物を備える機械装置を提供することにある。 Accordingly, an object of the present invention is to provide an alloy material capable of improving mechanical properties in a high-temperature environment, an alloy product using the alloy material, and a mechanical device provided with the alloy product.
　（Ｉ）本発明の一態様は、Ｃｏ、Ｃｒ、Ｆｅ、及びＮｉをそれぞれ５原子％以上４０原子％以下の範囲で含み、Ｍｏを０原子％超８原子％以下の範囲で含み、Ｔｉを１原子％以上１０原子％以下の範囲で含み、Ｂを０原子％超０．１５原子％未満の範囲で含み、Ｔａ及びＮｂの少なくとも一種を４原子％以下で含むか又は含まず、残部が不可避的不純物からなることを特徴とする合金材である。 (I) One embodiment of the present invention contains Co, Cr, Fe, and Ni each in a range of 5 atomic % or more and 40 atomic % or less, Mo in a range of more than 0 atomic % and 8 atomic % or less, and Ti. 1 atomic% or more and 10 atomic% or less, contains B in a range of more than 0 atomic% and less than 0.15 atomic%, contains or does not contain at least one of Ta and Nb in 4 atomic% or less, and the balance is The alloy material is characterized by containing unavoidable impurities.
　本発明は、上記合金材（Ｉ）において、以下のような改良や変更を加えることができる。
（ｉ）前記Ｂを０．０３原子％以上０．１２原子％以下の範囲で含む。
（ｉｉ）Ｔａ及びＮｂの少なくとも一種を４原子％以下で含む。
（ｉｉｉ）前記Ｔｉと、前記Ｔａ及びＮｂの少なくとも一種との合計が３原子％以上１０原子％以下である。
（ｉｖ）前記Ｃｏを２５原子％以上３８原子％以下の範囲で含み、前記Ｃｒを１６原子％以上２３原子％以下の範囲で含み、前記Ｆｅを１２原子％以上２０原子％以下の範囲で含み、前記Ｎｉを１７原子％以上２８原子％以下の範囲で含み、前記Ｍｏを１原子％以上７原子％以下の範囲で含み、前記Ｔｉを２原子％以上９原子％以下の範囲で含む。 In the present invention, the following improvements and changes can be added to the alloy material (I).
(i) B is contained in the range of 0.03 atomic % or more and 0.12 atomic % or less.
(ii) contains at least one of Ta and Nb at 4 atomic % or less;
(iii) The total content of Ti and at least one of Ta and Nb is 3 atomic % or more and 10 atomic % or less.
(iv) containing Co in a range of 25 atomic % or more and 38 atomic % or less, containing Cr in a range of 16 atomic % or more and 23 atomic % or less, and containing Fe in a range of 12 atomic % or more and 20 atomic % or less; , Ni in the range of 17 atomic % to 28 atomic %, Mo in the range of 1 atomic % to 7 atomic %, and Ti in the range of 2 atomic % to 9 atomic %.
　（ＩＩ）本発明の他の一態様は、上記の合金材を用いた合金製造物であって、
　上記合金製造物の母相結晶粒中に平均粒径１３０ｎｍ以下の極小粒子が分散析出していることを特徴とする合金製造物である。 (II) Another aspect of the present invention is an alloy product using the above alloy material,
An alloy product characterized in that extremely small particles having an average particle size of 130 nm or less are dispersed and precipitated in the parent phase crystal grains of the alloy product.
　（ＩＩＩ）本発明のさらに他の一態様は、上記の合金製造物を備える機械装置である。
　本明細書は本願の優先権の基礎となる日本国特許出願番号2021-096053号の開示内容を包含する。 (III) Yet another aspect of the present invention is a mechanical device comprising the alloy product described above.
This specification includes the disclosure of Japanese Patent Application No. 2021-096053, which is the basis of priority of this application.
　本発明によれば、合金材、合金材を用いた合金製造物、及び合金製造物を備える機械装置の高温環境下における機械的特性を向上できる。 According to the present invention, it is possible to improve the mechanical properties of an alloy material, an alloy product using the alloy material, and a mechanical device provided with the alloy product in a high-temperature environment.
実施形態に係る合金製造物の製造方法の一例を示す概略工程図である。BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic process drawing which shows an example of the manufacturing method of the alloy product which concerns on embodiment. 合金加工物Ｗ１の切断片の処理断面のＳＥＭ観察により得られる二次電子像である。2 is a secondary electron image obtained by SEM observation of a treated cross section of a cut piece of alloy workpiece W1. 合金加工物Ｗ３の切断片の処理断面のＳＥＭ観察により得られる二次電子像である。It is a secondary electron image obtained by SEM observation of the treated cross section of the cut piece of the alloy workpiece W3. ＳＴＥＭ観察により得られる母相結晶粒の電子回折パターンである。It is an electron diffraction pattern of the mother phase crystal grains obtained by STEM observation. ＳＴＥＭ観察により得られる母相結晶粒の暗視野像（ＤＦ－ＳＴＥＭ）である。2 is a dark-field image (DF-STEM) of matrix phase crystal grains obtained by STEM observation. エネルギー分散型Ｘ線分光法（ＥＤＸ：Energy Dispersive X-ray Spectroscopy）により母相結晶粒中の極小粒子の元素マッピングを行った結果を示す画像である。4 is an image showing the results of elemental mapping of extremely small particles in the matrix crystal grains by Energy Dispersive X-ray Spectroscopy (EDX). ＳＩＭＳ（Secondary Ion Mass Spectroscopy）による元素分布の定性評価により得られるＢＯ２ －イオン強度分布を示す画像である。2 is an image showing a BO 2 − ion intensity distribution obtained by qualitative evaluation of elemental distribution by SIMS (Secondary Ion Mass Spectroscopy). 図５の各図のＢＯ２ －イオン強度分布に挿入した矢印に沿う各位置のＢＯ２ －イオン強度分布を示すグラフである。FIG. 6 is a graph showing the BO 2 − ion intensity distribution at each position along the arrow inserted in the BO 2 − ion intensity distribution of each figure in FIG. 5;
　本発明者等は、従来の合金材をベースにして、様々な応用を検討した。その結果、環境温度が高くなるに従い、合金製造物の機械的特性が低下することが確認された。その要因について種々調査し考察した結果、この現象は、環境温度が高くなるに従い、破壊起点となる結晶粒界の強度が低下することが影響していると考えた。その上で、特定の組成とすることにより、結晶粒界の強度を向上させることができ、高温環境下における合金製造物の機械的特性を向上できることに想到した。本発明はこれらの知見を元になされたものである。 The inventors examined various applications based on conventional alloy materials. As a result, it was confirmed that the mechanical properties of the alloy products deteriorated as the environmental temperature increased. As a result of various investigations and considerations on the cause, it was thought that this phenomenon is affected by the decrease in the strength of the grain boundary, which is the starting point of fracture, as the environmental temperature rises. In addition, the inventors have come up with the idea that the specific composition can improve the strength of the grain boundary and improve the mechanical properties of the alloy product in a high-temperature environment. The present invention is made based on these findings.
（本発明の基本思想）
　上記のように従来のハイエントロピー合金を用いた合金材から製造された合金製造物では、環境温度が高くなるにつれて、機械的特性が低下する傾向がある。その要因について種々調査し考察した結果、この現象は、環境温度が高くなるにつれて結晶粒界の強度が低下することが影響していると考えられた。 (Basic idea of the present invention)
As described above, alloy products manufactured from alloy materials using conventional high-entropy alloys tend to have lower mechanical properties as the environmental temperature increases. As a result of various investigations and considerations on the cause, it was considered that this phenomenon is affected by the decrease in the strength of the grain boundary as the environmental temperature rises.
　一方、合金製造物の信頼性の観点から、合金製造物が高温環境下（例えば、７００℃）においても高い機械的特性を有することが好ましく、そのためには、高温環境下において破壊起点となり得る結晶粒界の強度を向上させることが望ましい。 On the other hand, from the viewpoint of the reliability of the alloy product, it is preferable that the alloy product has high mechanical properties even in a high temperature environment (for example, 700 ° C.). It is desirable to improve the strength of grain boundaries.
　そこで、本発明者等は、結晶粒界の強度を向上させるため、異種元素を添加した際の金属組織の変化や高温環境下における合金製造物の機械的特性の変化を鋭意研究した。その結果、Ｂ（ホウ素）を適切な範囲で含有させることで、結晶粒界の強度を向上させることができることを見出した。これにより、高温環境下における機械的特性（例えば、引張強度、破断伸び等）を向上できた。本発明は、当該知見と結果に基づくものである。 Therefore, in order to improve the strength of the grain boundaries, the present inventors diligently studied changes in the metal structure when different elements were added and changes in the mechanical properties of the alloy product in a high-temperature environment. As a result, it was found that the strength of grain boundaries can be improved by containing B (boron) in an appropriate range. As a result, the mechanical properties (eg, tensile strength, elongation at break, etc.) under high-temperature environments could be improved. The present invention is based on the findings and results.
　以下、本発明の合金材、合金製造物、及び機械装置に係る実施形態について図面を参照しながら具体的に説明する。ただし、本発明は、ここで取り挙げた実施形態に限定されるものではなく、その発明の技術的思想を逸脱しない範囲で公知技術と適宜組み合わせたり公知技術に基づいて改良したりすることができる。 Hereinafter, embodiments of the alloy material, alloy product, and mechanical device of the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to the embodiments mentioned here, and can be appropriately combined with known techniques or improved based on known techniques without departing from the technical idea of the invention. .
［合金材の組成］
　実施形態に係る合金材は、Ｃｏ、Ｃｒ、Ｆｅ、及びＮｉをそれぞれ５原子％以上４０原子％以下の範囲で含み、Ｍｏを０原子％超８原子％以下の範囲で含み、Ｔｉを１原子％以上１０原子％以下の範囲で含み、Ｂを０原子％超０．１５原子％未満の範囲で含み、Ｔａ及びＮｂの少なくとも一種を４原子％以下で含むか又は含まず、残部が不可避的不純物からなる。 [Composition of alloy material]
The alloy material according to the embodiment contains Co, Cr, Fe, and Ni in a range of 5 atomic % or more and 40 atomic % or less, Mo in a range of more than 0 atomic % and 8 atomic % or less, and 1 atom of Ti. % or more and 10 atomic % or less, contains B in a range of more than 0 atomic % and less than 0.15 atomic %, contains or does not contain at least one of Ta and Nb at 4 atomic % or less, and the balance is unavoidable Consists of impurities.
　Ｃｏ、Ｃｒ、Ｆｅ、及びＮｉは、基本的に合金材又は合金製造物の母相結晶粒を構成する主成分元素であり、カクテル効果による耐腐食性の向上に寄与していると考えられる。以下、合金材におけるこれらの成分元素の含有量について具体的に説明する。なお、下記する成分元素の上限値と下限値は任意に組み合わせることができる。また、好ましい範囲、より好ましい範囲、及びさらに好ましい範囲も適宜組み合わせることができる。 Co, Cr, Fe, and Ni are basically the main component elements that constitute the parent phase crystal grains of the alloy material or alloy product, and are believed to contribute to the improvement of corrosion resistance due to the cocktail effect. The contents of these component elements in the alloy material will be specifically described below. The upper limit and lower limit of the component elements described below can be combined arbitrarily. Moreover, the preferred range, the more preferred range, and the further preferred range can be combined as appropriate.
　Ｃｏの含有量は、２０原子％以上４０原子％以下が好ましく、２５原子％以上３８原子％以下がより好ましく、３０原子％以上３６原子％以下がさらに好ましい。 The Co content is preferably 20 atomic % or more and 40 atomic % or less, more preferably 25 atomic % or more and 38 atomic % or less, and even more preferably 30 atomic % or more and 36 atomic % or less.
　Ｃｒの含有量は、１０原子％以上２５原子％以下が好ましく、１６原子％以上２３原子％以下がより好ましく、１８原子％以上２１原子％以下がさらに好ましい。 The Cr content is preferably 10 atomic % or more and 25 atomic % or less, more preferably 16 atomic % or more and 23 atomic % or less, and further preferably 18 atomic % or more and 21 atomic % or less.
　Ｆｅの含有量は、１０原子％以上２５原子％以下が好ましく、１２原子％以上２０原子％以下がより好ましく、１４原子％以上１７原子％以下がさらに好ましい。 The Fe content is preferably 10 atomic % or more and 25 atomic % or less, more preferably 12 atomic % or more and 20 atomic % or less, and even more preferably 14 atomic % or more and 17 atomic % or less.
　Ｎｉの含有量は、１５原子％以上３０原子％以下が好ましく、１７原子％以上２８原子％以下がより好ましく、２１原子％以上２６原子％以下がさらに好ましい。 The Ni content is preferably 15 atomic % or more and 30 atomic % or less, more preferably 17 atomic % or more and 28 atomic % or less, and still more preferably 21 atomic % or more and 26 atomic % or less.
　Ｍｏは、Ｃｒと共に耐腐食性の向上に寄与していると考えられる。合金材におけるＭｏの含有量は、１原子％以上７原子％以下がより好ましく、２原子％以上５原子％以下がさらに好ましい。 It is believed that Mo contributes to the improvement of corrosion resistance together with Cr. The content of Mo in the alloy material is more preferably 1 atomic % or more and 7 atomic % or less, and further preferably 2 atomic % or more and 5 atomic % or less.
　Ｔｉは、母相結晶粒の中に分散析出する極小粒子を構成する成分であり、合金材の強度向上に寄与していると考えられる。しかし、含有量が高くなると所定の金属間化合物相の粗大粒成長や凝集析出を誘発し易くなる。具体的にはしたがって、合金材におけるＴｉの含有量は、１原子％以上１０原子％以下が良く、１原子％以上９原子％以下が好ましく、２原子％以上９原子％以下がより好ましく、２原子％以上７原子％以下がさらに好ましい。２原子％以上５原子％以下がさらにより好ましい。 Ti is a component that constitutes microscopic particles dispersed and precipitated in the matrix crystal grains, and is considered to contribute to the strength improvement of the alloy material. However, when the content becomes high, coarse grain growth and cohesive precipitation of the predetermined intermetallic compound phase are likely to be induced. Specifically, therefore, the Ti content in the alloy material is preferably 1 atomic % or more and 10 atomic % or less, preferably 1 atomic % or more and 9 atomic % or less, more preferably 2 atomic % or more and 9 atomic % or less. Atomic % or more and 7 atomic % or less are more preferable. 2 atomic % or more and 5 atomic % or less is even more preferable.
　Ｂ（ボロン）は、結晶粒界の電子構造を改善するなどの作用を生じさせることにより、結晶粒界の強度の向上に寄与していると考えられる。このため、合金材が、Ｂを０原子％超０．１５原子％未満の範囲で含む場合には、高温環境下における合金製造物の機械的特性を向上できる。また、Ｂの含有量が０．１５原子％未満である場合には、合金製造物に粗大な析出物が生成することを抑制することができ、室温環境下における合金製造物の機械的特性の低下を抑制できる。さらに、この場合には、積層造形プロセスでの積層造形体（成形体）の造形時だけでなく他のプロセスでの成形体の成形時においても、Ｂの含有を原因とする割れが成形体に生成することを抑制できる。Ｂの含有量は、極微量（０．０１原子％程度）でも上記の効果を得られるが、０．０３原子％以上０．１２原子％以下が好ましく、０．０５原子％以上０．１０原子％以下がより好ましい。また、Ｂを０．１５原子％以上添加した場合、粗大粒子ができる場合があり、温度に限らず機械的特性、特に伸びが低下する可能性がある。 It is believed that B (boron) contributes to improving the strength of the grain boundaries by producing effects such as improving the electronic structure of the grain boundaries. Therefore, when the alloy material contains B in a range of more than 0 atomic % and less than 0.15 atomic %, the mechanical properties of the alloy product can be improved in a high temperature environment. In addition, when the B content is less than 0.15 atomic %, it is possible to suppress the formation of coarse precipitates in the alloy product, and the mechanical properties of the alloy product in a room temperature environment can be improved. Decrease can be suppressed. Furthermore, in this case, cracks caused by the inclusion of B occur in the molded body not only during the molding of the laminated body (molded body) in the layered manufacturing process but also during the molding of the molded body in other processes. You can suppress the generation. Although the above effects can be obtained even when the content of B is extremely small (about 0.01 atomic percent), it is preferably 0.03 atomic percent or more and 0.12 atomic percent or less, and 0.05 atomic percent or more and 0.10 atomic percent. % or less is more preferable. Moreover, when 0.15 atomic % or more of B is added, coarse particles may be formed, and there is a possibility that the mechanical properties, particularly the elongation, are lowered regardless of the temperature.
　合金材は、Ｔａ及びＮｂの少なくとも一種をさらに含むことができる。原子サイズの大きいＴａ及びＮｂの少なくとも一種を添加することにより、固溶強化により合金材を用いた合金製造物の機械的特性をさらに向上できる。さらに、合金材の不働態皮膜が強化され耐孔食性が改善する効果も有する。一方で、Ｔａ及びＮｂはＴｉと同様に所定の金属間化合物相を構成する成分であるため、Ｔａ、Ｎｂ、Ｔｉの合計量を所定値以下とすることにより金属間化合物相の析出を制御することが良い。よって、合金材にＴａ及びＮｂの少なくとも一種を含む場合には、Ｔａ及びＮｂの少なくとも一種の含有量（Ｔａ及びＮｂの二種を含む場合には、Ｔａ及びＮｂの合計の含有量）は、０原子％より大きく４原子％以下の範囲とするのが良い。０．５原子％以上３原子％以下の範囲がより好ましく、１原子％以上２．５原子％以下の範囲がさらに好ましい。また、合金材は、Ｔａ及びＮｂの少なくとも一種を４原子％以下で含む場合には、Ｔｉと、Ｔａ及びＮｂの少なくとも一種とを共に含む金属間化合物の析出量を制御するために、Ｔｉと、Ｔａ及びＮｂの少なくとも一種との合計が３原子％以上１０原子％以下であるものがよい。なお、合金材としては、Ｔａ及びＮｂの少なくとも一種をさらに含むものの中でも、Ｔａをさらに含むものが好ましい。Ｔａをさらに含むことで、ＣｒＭｏによる不動態被膜を強化でき、合金の耐食性向上効果が得られるからである。 The alloy material can further contain at least one of Ta and Nb. By adding at least one of Ta and Nb having a large atomic size, the mechanical properties of the alloy product using the alloy material can be further improved by solid-solution strengthening. Furthermore, it has the effect of strengthening the passive film of the alloy material and improving the pitting corrosion resistance. On the other hand, since Ta and Nb, like Ti, are components that form a predetermined intermetallic compound phase, precipitation of the intermetallic compound phase is controlled by setting the total amount of Ta, Nb, and Ti to a predetermined value or less. that's good Therefore, when the alloy material contains at least one of Ta and Nb, the content of at least one of Ta and Nb (when both Ta and Nb are included, the total content of Ta and Nb) is It is preferable to make the range greater than 0 atomic % and 4 atomic % or less. The range of 0.5 atomic % or more and 3 atomic % or less is more preferable, and the range of 1 atomic % or more and 2.5 atomic % or less is even more preferable. In addition, when the alloy material contains at least one of Ta and Nb at 4 atomic % or less, Ti and , Ta and Nb in a total amount of 3 atomic % or more and 10 atomic % or less. As the alloy material, among those further containing at least one of Ta and Nb, those further containing Ta are preferable. This is because by further including Ta, the passivation film of CrMo can be strengthened, and the effect of improving the corrosion resistance of the alloy can be obtained.
　合金材は、主成分として、上記Ｃｏを２５原子％以上３８原子％以下の範囲で含み、上記Ｃｒを１６原子％以上２３原子％以下の範囲で含み、上記Ｆｅを１２原子％以上２０原子％以下の範囲で含み、上記Ｎｉを１７原子％以上２８原子％以下の範囲で含み、副成分として、上記Ｍｏを１原子％以上７原子％以下の範囲で含み、上記Ｔｉを２原子％以上９原子％以下の範囲で含むものがより好ましい。 The alloy material contains, as main components, Co in the range of 25 atomic % to 38 atomic %, Cr in the range of 16 atomic % to 23 atomic %, and Fe in the range of 12 atomic % to 20 atomic %. It contains the Ni in the range of 17 atomic % or more and 28 atomic % or less, contains the Mo in the range of 1 atomic % or more and 7 atomic % or less, and contains the Ti in the range of 2 atomic % or more and 9 atomic % as an auxiliary component. It is more preferable to contain in the range of atomic % or less.
　「不可避的不純物」とは、完全に除去することは困難であるが可能な限り低減することが望ましい成分元素を言う。不可避的不純物としては、例えば、Ｓｉ（ケイ素）、Ｐ（リン）、Ｓ（硫黄）、Ｎ（窒素）、Ｏ（酸素）等が挙げられる。合金材に含まれる不可避的不純物の合計の含有量は、１質量％以下が好ましい。言い換えると、合金材に意図的に含有させる成分元素の合計の含有量は、９９質量％以上が好ましい。以下、合金材に含まれる不可避的不純物の含有量についてより具体的に説明する。 "Inevitable impurities" refer to component elements that are difficult to remove completely, but that should be reduced as much as possible. Examples of unavoidable impurities include Si (silicon), P (phosphorus), S (sulfur), N (nitrogen), O (oxygen), and the like. The total content of unavoidable impurities contained in the alloy material is preferably 1% by mass or less. In other words, the total content of the constituent elements intentionally contained in the alloy material is preferably 99% by mass or more. The content of unavoidable impurities contained in the alloy material will be described in more detail below.
　Ｓｉの含有量は、０．２質量％以下が好ましく、０．１質量％以下がより好ましく、０．０５質量％以下がさらに好ましい。Ｐの含有量は、０．１質量％以下が好ましく、０．０５質量％以下がより好ましく、０．０２質量％以下がさらに好ましい。Ｓの含有量は、０．１質量％以下が好ましく、０．０５質量％以下がより好ましく、０．０２質量％以下がさらに好ましい。Ｎの含有量は、０．１質量％以下が好ましく、０．０５質量％以下がより好ましく、０．０２質量％以下がさらに好ましい。Ｏの含有量は、０．２質量％以下が好ましく、０．１質量％以下がより好ましく、０．０５質量％以下がさらに好ましい。 The Si content is preferably 0.2% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less. The P content is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.02% by mass or less. The S content is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.02% by mass or less. The N content is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.02% by mass or less. The O content is preferably 0.2% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less.
［合金材を用いた合金製造物］
　実施形態に係る合金製造物は、上記の実施形態に係る合金材を用いた合金製造物であって、母相結晶粒を含む微細組織を有するものである。合金製造物では、合金材がＢを含んでいるため、結晶粒界の強度を向上させることができる。よって、高温環境下における機械的特性が向上した合金製造物である。 [Alloy product using alloy material]
The alloy product according to the embodiment is an alloy product using the alloy material according to the above embodiment, and has a microstructure containing parent phase crystal grains. In the alloy product, since the alloy material contains B, the strength of the grain boundaries can be improved. Therefore, it is an alloy product with improved mechanical properties in a high-temperature environment.
（微細組織）
　合金製造物の微細組織は、母相結晶粒を含むものであれば特に限定されないが、母相結晶粒中に極小粒子が分散析出しているものが好ましい。機械的特性等がより向上するからである。積層造形による合金製造物の場合、極小粒子が析出し易いと言う特徴がある。 (microstructure)
The microstructure of the alloy product is not particularly limited as long as it contains mother phase crystal grains, but it is preferable to have microscopic particles dispersed and precipitated in the mother phase crystal grains. This is because the mechanical properties and the like are further improved. In the case of alloy products produced by additive manufacturing, there is a feature that very small particles tend to precipitate.
　極小粒子は、母相結晶粒中において他の部分より所定の成分元素が濃化しているＬ１２型規則相の結晶性粒子であり、例えば、母相結晶粒中において他の部分よりＮｉ及びＴｉが濃化している結晶性粒子である。極小粒子の平均粒径は、例えば、１３０ｎｍ以下が好ましく、１０ｎｍ以上１３０ｎｍ以下がより好ましく、２０ｎｍ以上１００ｎｍ以下がさらに好ましい。極小粒子の平均粒径がこれらの範囲であることにより、機械的特性等がよりいっそう向上するからである。ここで、極小粒子の平均粒径は、例えば、ＳＴＥＭ観察により得られる母相結晶粒の暗視野像（ＤＦ－ＳＴＥＭ）等の観察像において、最大径（最大長さ）が５ｎｍ以上の少なくとも５つの極小粒子を選択した上で、それらの少なくとも５つの極小粒子の最大径（最大長さ）を測定し、それらの最大径の平均として求められる。 The ultra-small particles are crystalline particles of the L12 type ordered phase in which a predetermined component element is concentrated more than other parts in the mother phase crystal grains. Concentrated crystalline particles. The average particle size of the ultra-small particles is, for example, preferably 130 nm or less, more preferably 10 nm or more and 130 nm or less, and even more preferably 20 nm or more and 100 nm or less. This is because the mechanical properties and the like are further improved when the average particle size of the extremely small particles is within these ranges. Here, the average particle diameter of the extremely small particles is, for example, a dark field image (DF-STEM) of the mother phase crystal grains obtained by STEM observation, and the maximum diameter (maximum length) is at least 5 nm or more. After selecting one microparticle, the maximum diameter (maximum length) of at least five microparticles is measured, and the average of the maximum diameters is obtained.
　母相結晶粒は、特に限定されないが、例えば、結晶構造として面心立方晶（ＦＣＣ）を有し、平均結晶粒径が３００μｍ以下であるものが好ましい。面心立方晶は最密充填構造の一種であるため、母相結晶粒が結晶構造として面心立方晶を有する場合、機械的特性等が向上するからである。平均結晶粒径が３００μｍ以下の場合、機械的特性や耐腐食性等が向上する。平均結晶粒径は、２００μｍ以下がより好ましく、１５０μｍ以下がさらに好ましい。機械的特性や耐腐食性等がさらに向上するからである。なお、母相結晶粒は、結晶構造として、面心立方晶に加えて、単純立方晶（ＳＣ）を有するものでもよい。 Although the parent phase crystal grains are not particularly limited, for example, those having a face-centered cubic (FCC) crystal structure and an average crystal grain size of 300 μm or less are preferable. This is because face-centered cubic crystals are one type of close-packed structure, and mechanical properties and the like are improved when the mother phase crystal grains have a face-centered cubic crystal structure. When the average crystal grain size is 300 μm or less, mechanical properties, corrosion resistance, etc. are improved. The average crystal grain size is more preferably 200 μm or less, and even more preferably 150 μm or less. This is because the mechanical properties, corrosion resistance, etc. are further improved. The matrix crystal grains may have a simple cubic (SC) crystal structure in addition to the face-centered cubic crystal structure.
　実施形態に係る合金製造物としては、高温環境下における機械的特性を改良できることから、高温環境下で高い機械的特性が求められる部材が好ましい。このような部材としては、例えば、タービンブレード等を含むタービン用部材、ボイラ用部材、エンジン用部材、ノズル用部材、ケーシング、配管、バルブ等を含めたプラント用構造部材、発電機用構造部材、原子炉用構造部材、航空宇宙用構造部材、油圧機器用部材、軸受、ピストン、歯車、回転軸等の各種機器の機構部材などが好ましい。さらに、合金製造物としては、例えば、インペラ等の他の部材でもよい。 The alloy product according to the embodiment is preferably a member that requires high mechanical properties in a high temperature environment because it can improve the mechanical properties in a high temperature environment. Such members include, for example, turbine members including turbine blades, boiler members, engine members, nozzle members, casings, pipes, valves and the like, structural members for plants, structural members for generators, Structural members for nuclear reactors, structural members for aerospace, members for hydraulic equipment, bearings, pistons, gears, mechanical members for various devices such as rotating shafts, and the like are preferred. Furthermore, the alloy product may be, for example, another member such as an impeller.
［合金製造物を備える機械装置］
　実施形態に係る機械装置としては、高温環境下における機械的特性を改良できることから、高温環境下で高い機械的特性が求められる機械装置が好ましい。このような機械装置としては、例えば、タービン、ボイラ、エンジン、ノズル、プラント、発電機、原子炉、航空宇宙用装置、油圧機器、動力伝達装置、その他の各種機器などが好ましい。 [Machine equipped with an alloy product]
As the mechanical device according to the embodiment, a mechanical device that requires high mechanical properties in a high-temperature environment is preferable because it can improve the mechanical properties in a high-temperature environment. Preferred examples of such mechanical devices include turbines, boilers, engines, nozzles, plants, generators, nuclear reactors, aerospace devices, hydraulic devices, power transmission devices, and other various devices.
［合金製造物の製造方法］
　図１は、実施形態に係る合金製造物の製造方法の一例を示す概略工程図である。
　実施形態に係る合金製造物の製造方法は、図１に示す一例のように、概略的に、合金材作製工程Ｓ１と成形加工工程Ｓ２とを少なくとも備え、成形加工プロセスに応じて擬溶体化熱処理工程Ｓ３又は焼結工程Ｓ４をさらに備える。さらに、実施形態に係る合金製造物の製造方法は、図１に示す一例のように、擬溶体化熱処理工程Ｓ３をさらに備える場合には、時効熱処理工程Ｓ５を備えることもできる。以下、各工程をより具体的に説明する。 [Manufacturing method of alloy product]
FIG. 1 is a schematic process diagram showing an example of a method for manufacturing an alloy product according to an embodiment.
The method for manufacturing an alloy product according to the embodiment, as in the example shown in FIG. 1, generally includes at least an alloy material preparation step S1 and a forming step S2, and performs a quasi-solution heat treatment according to the forming process. It further includes step S3 or sintering step S4. Furthermore, the method for manufacturing an alloy product according to the embodiment can also include an aging heat treatment step S5 when further including the quasi-solution heat treatment step S3 as in the example shown in FIG. Each step will be described in more detail below.
（合金材作製工程）
　合金材作製工程Ｓ１では、合金製造物の材料となる合金材を作製する。合金材作製工程Ｓ１は、所望の合金製造物を製造できる合金材が得られる限り詳細手順に特段の限定はないが、例えば、所望の合金組成となるように原料金属を混合し、溶解して溶湯を得る原料混合溶解工程Ｓ１ａと、溶湯を凝固させて合金材を得る合金凝固工程Ｓ１ｂとを含む工程である。 (Alloy material manufacturing process)
In the alloy material producing step S1, an alloy material that will be the material of the alloy product is produced. In the alloy material production step S1, there is no particular limitation on the detailed procedure as long as an alloy material capable of producing a desired alloy product is obtained. This process includes a raw material mixing and melting step S1a for obtaining molten metal, and an alloy solidification step S1b for obtaining an alloy material by solidifying the molten metal.
　原料混合溶解工程Ｓ１ａは、原料金属を混合し、溶解して溶湯が得られる工程であれば特段の限定はないが、例えば、合金中の不純物成分の含有率をより低減する（合金を精錬する）ため、原料金属を混合し、一旦溶解して溶湯を得る溶解工程と、該溶湯を一旦凝固させて再溶解用合金塊を形成する合金塊形成工程と、該再溶解用合金塊を再溶解して清浄化された溶湯を得る再溶解工程とを含む工程でもよい。再溶解方法は、合金の清浄度を高められる限り特段の限定はないが、例えば、真空アーク再溶解（ＶＡＲ）等が好ましい。 The raw material mixing and melting step S1a is not particularly limited as long as the raw material metal is mixed and melted to obtain a molten metal. ), a melting step of mixing raw metals and once melting to obtain a molten metal, an alloy ingot forming step of once solidifying the molten metal to form an alloy ingot for remelting, and remelting the alloy ingot for remelting and a remelting step of obtaining a cleaned molten metal. The remelting method is not particularly limited as long as the cleanliness of the alloy can be improved, but for example, vacuum arc remelting (VAR) is preferred.
　合金凝固工程Ｓ１ｂで溶湯を凝固させる方法としては、成形加工工程Ｓ２で用いるのに適した形態（例えば、合金塊（インゴット）、合金粉末等）の合金材が得られる限り特段の限定はないが、例えば、鋳造法により、溶湯を凝固させることで合金材として合金塊を得る方法、アトマイズ法により、溶湯を飛散、凝固させて合金材として合金粉末を得る方法などが好ましい。 The method of solidifying the molten metal in the alloy solidification step S1b is not particularly limited as long as the alloy material is obtained in a form suitable for use in the forming step S2 (for example, an alloy lump (ingot), alloy powder, etc.). For example, a method of obtaining an alloy ingot as an alloy material by solidifying the molten metal by a casting method, a method of obtaining an alloy powder as an alloy material by scattering and solidifying the molten metal by an atomizing method, and the like are preferable.
　アトマイズ法により合金粉末を得る場合、次工程の成形加工工程Ｓ２で合金粉末を用いた成形加工（例えば、粉末冶金プロセス、積層造形プロセス等）を行う際の合金粉末の流動性や充填性の観点から、合金粉末の平均粒径を５μｍ以上２００μｍ以下の範囲とすることが好ましく、１０μｍ以上１００μｍ以下の範囲とすることがより好ましく、１０μｍ以上５０μｍ以下の範囲とすることがさらに好ましい。合金粉末の平均粒径を５μｍ以上とすることで、成形加工工程Ｓ２で合金粉末の流動性が保たれ、成形物の形状精度への影響が少ない。一方、合金粉末の平均粒径を２００μｍ以下とすることで、成形加工工程Ｓ２で合金粉末の充填性が保たれ、充填性の悪化に伴う成形物の内部空隙や表面粗化の発生を抑制できる。なお、このようなことから、合金粉末の平均粒径を５μｍ以上２００μｍ以下の範囲に分級する分級工程を、アトマイズ法により合金粉末を得た後にさらに行ってもよい。分級工程は必須の工程ではないが、合金粉末の利用性向上の観点から行うことが好ましい。なお、合金粉末の粒径分布を測定した結果、所望の範囲内にあることを確認した場合も、分級工程を行ったものと見なすことができる。 When the alloy powder is obtained by the atomization method, the flowability and filling properties of the alloy powder when performing the molding process using the alloy powder (for example, the powder metallurgy process, the additive manufacturing process, etc.) in the subsequent molding process step S2. Therefore, the average particle size of the alloy powder is preferably in the range of 5 μm to 200 μm, more preferably in the range of 10 μm to 100 μm, and even more preferably in the range of 10 μm to 50 μm. By setting the average particle diameter of the alloy powder to 5 μm or more, the fluidity of the alloy powder is maintained in the forming step S2, and the influence on the shape accuracy of the molded product is small. On the other hand, by setting the average particle diameter of the alloy powder to 200 μm or less, the filling property of the alloy powder is maintained in the molding process step S2, and the occurrence of internal voids and surface roughening of the molded product due to deterioration of the filling property can be suppressed. . For this reason, a classification step of classifying the average particle size of the alloy powder into a range of 5 μm or more and 200 μm or less may be further performed after the alloy powder is obtained by the atomization method. Although the classification step is not an essential step, it is preferably performed from the viewpoint of improving the usability of the alloy powder. In addition, even when it is confirmed that the particle size distribution of the alloy powder is within the desired range as a result of measuring the particle size distribution, it can be considered that the classification step has been performed.
（成形加工工程）
　成形加工工程Ｓ２では、合金材作製工程Ｓ１で得られた合金材から所望形状の成形体を成形する。なお。実施形態に係る合金製造物の製造方法は、成形加工工程Ｓ２で成形された成形体をそのまま合金製造物として製造するものでもよい。 (Molding process)
In the forming step S2, a formed body having a desired shape is formed from the alloy material obtained in the alloy material producing step S1. note that. The method for manufacturing an alloy product according to the embodiment may be one in which the molded body formed in the forming step S2 is directly manufactured as an alloy product.
　合金材から成形体を成形する方法としては、所望形状の成形体が成形できる限り特段の限定はなく、合金材の種類により異なるが、例えば、合金材が合金塊の場合、合金材から成形体を成形する方法としては、切断加工、塑性加工（例えば、鍛造加工、引抜加工、圧延加工等）、機械加工（例えば、打抜加工、切削加工等）などを施して合金加工体を成形体として成形する方法でもよい。 The method for forming a molded body from an alloy material is not particularly limited as long as a molded body having a desired shape can be formed, and varies depending on the type of alloy material. As a method of molding, cutting, plastic working (e.g., forging, drawing, rolling, etc.), machining (e.g., punching, cutting, etc.), etc. are performed to make the alloy processed body into a molded body. A molding method may also be used.
　一方、合金材が合金粉末の場合、合金材から成形体を成形する方法としては、例えば、積層造形プロセス、粉末冶金プロセスなどが好ましい。積層造形プロセスは、特段の限定はなく、従前のプロセスを適宜利用できる。例えば、付加製造法（Additive manufacturing：ＡＭ法）により、合金粉末から所望形状を積層造形して積層造形体を成形するプロセスが挙げられる。これにより、焼結ではなく局所的に溶融し、急速に凝固（以下、「溶融凝固」ということがある。）することでニアネットシェイプの合金製造物を製造できる。積層造形プロセスは、鍛造材と同程度以上の機械的特性とともに複雑形状を有する三次元部材を直接的に製造できるという特徴がある。ＡＭ法としては、特段の限定はなく、従前のプロセスを適宜利用できる。例えば、選択的レーザ溶融法(Selective Laser Melting:ＳＬＭ)、電子ビーム積層造形法(Electron Beam Melting:ＥＢＭ)、レーザビーム粉末肉盛法(Laser Metal Deposition:ＬＭＤ)、指向性エネルギー堆積法（Directed energy deposition：ＤＥＤ）等を用いることができる。 On the other hand, when the alloy material is an alloy powder, the preferred method for forming a compact from the alloy material is, for example, an additive manufacturing process, a powder metallurgy process, or the like. The layered manufacturing process is not particularly limited, and conventional processes can be used as appropriate. For example, there is a process of laminating and molding a desired shape from alloy powder to form a lamination-molded body by an additive manufacturing (AM) method. As a result, instead of sintering, local melting and rapid solidification (hereinafter sometimes referred to as "melting and solidification") can be used to produce a near-net-shape alloy product. Additive manufacturing processes are characterized by the ability to directly produce three-dimensional parts with complex geometries with mechanical properties comparable to or better than forgings. The AM method is not particularly limited, and conventional processes can be used as appropriate. For example, Selective Laser Melting (SLM), Electron Beam Melting (EBM), Laser Metal Deposition (LMD), Directed energy deposition deposition: DED) or the like can be used.
　ＡＭ法としてＳＬＭを用いる積層造形プロセスを簡単に説明する。本積層造形プロセスは、合金粉末を敷き詰めて所定厚さの合金粉末床を用意する合金粉末床用意工程と、該合金粉末床の所定の領域にレーザ光を照射してこの領域の合金粉末を局所的に溶融し、急速に凝固させるレーザ溶融凝固工程と、を繰り返して積層造形体を形成する積層造形プロセスである。 We will briefly explain the additive manufacturing process using SLM as the AM method. This additive manufacturing process includes an alloy powder bed preparation step of spreading alloy powder to prepare an alloy powder bed having a predetermined thickness, and a laser beam irradiating a predetermined area of the alloy powder bed to localize the alloy powder in this area. It is a layered manufacturing process in which a layered body is formed by repeating a laser melting and solidifying process in which the material is melted and solidified rapidly.
　より具体的には、積層造形体の密度及び形状精度ができるだけ高くなるように、例えば、合金粉末床の厚さｈを０．０２ｍｍ以上０．２ｍｍ以下の範囲から選定し、レーザ光の出力Ｐを５０Ｗ以上１０００Ｗ以下の範囲から選定し、レーザ光の走査速度Ｓを５０ｍｍ／ｓ以上１００００ｍｍ／ｓ以下の範囲から選定し、レーザ光の走査間隔Ｌを０．０５ｍｍ以上０．２ｍｍ以下の範囲から選定する。そして、「Ｅ＝Ｐ／（ｈ×Ｓ×Ｌ）」で表される局所溶融の体積エネルギー密度Ｅを２０Ｊ／ｍｍ３以上２００Ｊ／ｍｍ３以下の範囲で制御することが好ましく、４０Ｊ／ｍｍ３以上１５０Ｊ／ｍｍ３以下の範囲で制御することがより好ましい。 More specifically, for example, the thickness h of the alloy powder bed is selected from the range of 0.02 mm or more and 0.2 mm or less so that the density and shape accuracy of the laminate-molded body are as high as possible, and the laser light output P is selected from the range of 50 W or more and 1000 W or less, the laser beam scanning speed S is selected from the range of 50 mm / s or more and 10000 mm / s or less, and the laser beam scanning interval L is selected from the range of 0.05 mm or more and 0.2 mm or less Select. Then, it is preferable to control the volume energy density E of local melting represented by “E = P / (h × S × L)” in the range of 20 J / mm 3 or more and 200 J / mm 3 or less, and 40 J / mm 3 It is more preferable to control in the range of 150 J/mm 3 or less.
　レーザ溶融凝固工程で造形した積層造形体は合金粉末床中に埋没している。このため、この積層造形プロセスは、レーザ溶融凝固工程の次に、合金粉末床から積層造形体を取り出す取出工程を備えていてもよい。積層造形体の取り出し方法は、特段の限定はなく従前の方法を利用できる。尚、ＥＢＭ法では、合金粉末を用いたサンドブラストを好ましく用いることができる。合金粉末を用いたサンドブラストは、除去した合金粉末床を吹き付けた合金粉末と共に解砕することで、合金粉末として再利用することができる利点がある。 The laminate-molded body produced by the laser melting and solidification process is buried in the alloy powder bed. For this reason, the additive manufacturing process may comprise, following the laser melting and solidification step, a removal step of removing the additively manufactured body from the alloy powder bed. There is no particular limitation on the method for taking out the layered product, and conventional methods can be used. In the EBM method, sandblasting using alloy powder can be preferably used. Sandblasting using alloy powder has the advantage that the removed alloy powder bed can be pulverized together with the blown alloy powder to be reused as alloy powder.
　粉末冶金プロセスとしては、特段の限定はなく、従前のプロセスを適宜利用できる。また、合金材が合金粉末の場合、成形物の形状精度を高めるため、積層造形プロセスや粉末冶金プロセス等による成形体に対して、切断加工、塑性加工、機械加工などをさらに行ってもよい。 There are no particular limitations on the powder metallurgy process, and conventional processes can be used as appropriate. Further, when the alloy material is an alloy powder, in order to improve the shape accuracy of the molded product, the molded product obtained by an additive manufacturing process, a powder metallurgy process, or the like may be further subjected to cutting, plastic working, machining, or the like.
（擬溶体化熱処理工程）
　擬溶体化熱処理工程Ｓ３では、合金塊から成形した成形体（合金加工体）又は合金粉末から積層造形プロセスで成形した成形体（積層造形体）に対して擬溶体化熱処理を行う。擬溶体化熱処理では、成形体を加熱することで所定温度に一定時間だけ保持する。これにより、成形体中に残存する偏析物や組成分布を均質化し、合金加工体から得られる合金加工物又は積層造形体から得られる合金造形物を合金製造物として製造する。なお、本発明の合金材については、現段階で学術的に確立された相平衡状態図等の知見が存在せず、偏析物が完全に溶体化する温度を正確に規定できない。このため、本熱処理の名称を擬溶体化熱処理と称している。 (Quasi-solution heat treatment step)
In the quasi-solution heat treatment step S3, a quasi-solution heat treatment is performed on a molded body (alloy processed body) molded from an alloy ingot or a molded body (laminated molded body) molded from an alloy powder by an additive manufacturing process. In the quasi-solution heat treatment, the compact is heated and held at a predetermined temperature for a certain period of time. As a result, the segregated substances remaining in the molded body and the composition distribution are homogenized, and an alloy processed product obtained from the alloy processed body or an alloy shaped product obtained from the layered structure is manufactured as an alloy product. Regarding the alloy material of the present invention, there is no scientifically established knowledge such as a phase equilibrium diagram at the present stage, and the temperature at which segregates are completely dissolved cannot be accurately defined. Therefore, the name of this heat treatment is called quasi-solution heat treatment.
　擬溶体化熱処理の温度は、特段の限定はないが、例えば、１０００℃以上１２５０℃以下の範囲が好ましく、１０５０℃以上１２００℃以下の範囲がより好ましく、１１００℃以上１１８０℃以下の範囲がさらに好ましい。擬溶体化熱処理の温度が１０００℃以上であれば、十分な均質化が可能である。また、擬溶体化熱処理の温度が１２５０℃以下であれば、母相結晶粒が粗大化せず、耐腐食性や機械的特性が向上する。擬溶体化熱処理の雰囲気は、特段の限定はなく、大気雰囲気でもよいし、非酸化性雰囲気（実質的に酸素がほとんど存在しない雰囲気、例えば、真空中や高純度アルゴン雰囲気や高純度窒素雰囲気等）でもよい。 The temperature of the quasi-solution heat treatment is not particularly limited, but for example, it is preferably in the range of 1000 ° C. or higher and 1250 ° C. or lower, more preferably in the range of 1050 ° C. or higher and 1200 ° C. or lower, and further preferably in the range of 1100 ° C. or higher and 1180 ° C. or lower. preferable. Sufficient homogenization is possible if the temperature of the quasi-solution heat treatment is 1000° C. or higher. Further, if the temperature of the quasi-solution heat treatment is 1250° C. or less, the matrix phase crystal grains do not coarsen, and corrosion resistance and mechanical properties are improved. The atmosphere of the quasi-solution heat treatment is not particularly limited, and may be an air atmosphere or a non-oxidizing atmosphere (an atmosphere in which substantially no oxygen is present, such as a vacuum, a high-purity argon atmosphere, a high-purity nitrogen atmosphere, etc. ) can be used.
　擬溶体化熱処理の保持時間は、被熱処理体の体積や熱容量及び熱処理の温度等を考慮しながら、０．１時間以上１００時間以下の範囲に適宜設定すればよい。なお、極小粒子の平均粒径を制御する観点から、擬溶体化熱処理での成形体の昇温過程では、金属間化合物相が成長し易い温度領域（例えば、８００℃以上９００℃以下の範囲）を可能な限り速く通過させることが好ましい。 The holding time of the quasi-solution heat treatment may be appropriately set within the range of 0.1 hours or more and 100 hours or less, taking into consideration the volume and heat capacity of the object to be heat treated, the temperature of the heat treatment, and the like. From the viewpoint of controlling the average particle size of the extremely small particles, in the process of raising the temperature of the molded body in the pseudo-solution heat treatment, the temperature range where the intermetallic compound phase easily grows (for example, the range of 800 ° C. or higher and 900 ° C. or lower) is preferably passed through as quickly as possible.
　なお、擬溶体化熱処理では、成形体を加熱することで所定温度に一定時間だけ保持した後に、空冷等により急冷してもよい。 In the quasi-solution heat treatment, the molded body may be heated to maintain a predetermined temperature for a certain period of time, and then quenched by air cooling or the like.
（時効熱処理工程）
　なお、実施形態に係る合金製造物の製造方法では、擬溶体化熱処理工程Ｓ３の後には、合金塊から成形した成形体（合金加工体）又は合金粉末から積層造形プロセスで成形した成形体（積層造形体）に対して時効熱処理を施す時効熱処理工程Ｓ５を追加することもできる。時効熱処理工程Ｓ５において、時効熱処理の対象は擬溶体化熱処理を施した成形体としても良い。時効熱処理では、成形体を加熱することで所定温度に一定時間だけ保持する。これにより、成形体中の母相結晶粒中に極小粒子他の析出物を生成または成長させる。このようにして、合金加工体から得られる合金加工物又は積層造形体から得られる合金造形物を合金製造物として製造する。 (Aging heat treatment process)
In the method for manufacturing an alloy product according to the embodiment, after the quasi-solution heat treatment step S3, a molded body (alloy processed body) molded from an alloy ingot or a molded body molded from alloy powder in a layered manufacturing process (laminated It is also possible to add an aging heat treatment step S5 in which aging heat treatment is performed on the shaped body). In the aging heat treatment step S5, the target of the aging heat treatment may be a molded body subjected to quasi-solution heat treatment. In the aging heat treatment, the compact is heated and held at a predetermined temperature for a certain period of time. As a result, microparticles and other precipitates are generated or grown in the mother phase crystal grains in the compact. In this way, an alloy processed product obtained from the alloy processed product or an alloy shaped product obtained from the layered product is manufactured as an alloy product.
　時効熱処理の温度は、特段の限定はないが、例えば、５００℃以上９００℃以下の範囲が好ましく、６００℃以上８５０℃以下の範囲がより好ましい。時効熱処理の温度が５００℃以上であれば、成形体中の母相結晶粒中の析出物に変化が生じる。また、擬溶体化熱処理の温度が９００℃以下であれば、析出物が過度に生成せず、耐腐食性や機械的特性が向上する。擬溶体化熱処理の雰囲気は、特段の限定はなく、大気雰囲気でもよいし、非酸化性雰囲気（実質的に酸素がほとんど存在しない雰囲気、例えば、真空中や高純度アルゴン雰囲気や高純度窒素雰囲気等）でもよい。 Although the temperature of the aging heat treatment is not particularly limited, it is preferably in the range of 500°C or higher and 900°C or lower, and more preferably in the range of 600°C or higher and 850°C or lower. If the temperature of the aging heat treatment is 500° C. or higher, the precipitates in the parent phase crystal grains in the compact are changed. Further, when the temperature of the quasi-solution heat treatment is 900° C. or less, excessive precipitates are not formed, and corrosion resistance and mechanical properties are improved. The atmosphere of the quasi-solution heat treatment is not particularly limited, and may be an air atmosphere or a non-oxidizing atmosphere (an atmosphere in which substantially no oxygen is present, such as a vacuum, a high-purity argon atmosphere, a high-purity nitrogen atmosphere, etc. ) can be used.
　時効熱処理の保持時間は、被熱処理体の体積や熱容量及び熱処理の温度等を考慮しながら、０．５時間以上２４時間以下の範囲に適宜設定すればよい。なお、時効熱処理では、成形体を加熱することで所定温度に一定時間だけ保持した後に、空冷等により急冷してもよい。 The holding time of the aging heat treatment may be appropriately set in the range of 0.5 hours or more and 24 hours or less, taking into consideration the volume and heat capacity of the body to be heat treated, the temperature of the heat treatment, and the like. In the aging heat treatment, the compact may be heated to a predetermined temperature and held for a certain period of time, and then rapidly cooled by air cooling or the like.
（焼結工程）
　焼結工程Ｓ４では、合金粉末から粉末冶金プロセスで成形した成形体を焼結する。これにより、合金焼結物を合金製造物として製造する。焼結方法としては、特段の限定はなく、従前の方法を適宜利用できる。焼結方法としては、成形加工工程Ｓ２と焼結工程Ｓ４とを完全に独立させて行う方法（成形加工工程Ｓ２で成形のみを行い、焼結工程Ｓ４で焼結のみを行う方法）でもよいし、例えば、熱間等方圧加圧法（ＨＩＰ）等のように成形加工工程Ｓ２と焼結工程Ｓ４とを一体的に行う方法でもよい。なお、前述の積層造形体については、焼結工程Ｓ４は省略することができる。他方ＨＩＰは実施することができる。ＨＩＰにより積層造形体中に内在する可能性のある空隙を減少することも可能である。 (Sintering process)
In the sintering step S4, the molded body formed by the powder metallurgy process is sintered from the alloy powder. Thereby, an alloy sintered product is produced as an alloy product. The sintering method is not particularly limited, and conventional methods can be used as appropriate. The sintering method may be a method in which the molding process step S2 and the sintering process S4 are performed completely independently (a method in which only molding is performed in the molding process step S2 and only sintering is performed in the sintering process S4). For example, a method such as hot isostatic pressing (HIP) or the like may be used in which the molding step S2 and the sintering step S4 are integrally performed. Note that the sintering step S4 can be omitted for the laminate-molded body described above. HIP, on the other hand, can be implemented. HIPing can also reduce voids that may be inherent in the laminate.
　焼結温度としては、特段の限定はないが、例えば、擬溶体化熱処理工程Ｓ３と同様の温度領域でよい。すなわち、焼結温度としては、例えば、１０００℃以上１２５０℃以下の範囲が好ましく、１０５０℃以上１２００℃以下の範囲がより好ましく、１１００℃以上１１８０℃以下の範囲がさらに好ましい。ＨＩＰを含む焼結工程後は空冷などのように出来る限り早く冷却することが好ましい。焼結工程で用いる設備の制約により十分な冷却速度が得られない場合は焼結工程の後に前述の擬溶体化処理工程Ｓ３を追加して、空冷等により急冷しても良い。 The sintering temperature is not particularly limited, but may be, for example, in the same temperature range as in the quasi-solution heat treatment step S3. That is, the sintering temperature is, for example, preferably in the range of 1000°C to 1250°C, more preferably in the range of 1050°C to 1200°C, and even more preferably in the range of 1100°C to 1180°C. After the sintering process including HIP, it is preferable to cool as soon as possible, such as air cooling. If a sufficient cooling rate cannot be obtained due to restrictions on equipment used in the sintering process, the quasi-solution treatment process S3 described above may be added after the sintering process, and rapid cooling may be performed by air cooling or the like.
（仕上工程）
　実施形態に係る合金製造物の製造方法は、図１に図示していないが、擬溶体化熱処理工程Ｓ３又は焼結工程Ｓ４で得られた合金製造物に対して表面仕上げ等を行う仕上げ工程を必要に応じてさらに備えてもよい。 (Finishing process)
Although not shown in FIG. 1, the method for manufacturing an alloy product according to the embodiment includes a finishing step of performing surface finishing and the like on the alloy product obtained in the quasi-solution heat treatment step S3 or the sintering step S4. Further may be provided as necessary.
　以下、本発明を実施例及び比較例に基づいて具体的に説明する。なお、本発明はこれら実施例に限定されるものではない。 The present invention will be specifically described below based on examples and comparative examples. However, the present invention is not limited to these examples.
［実験１］
（合金材Ａ１～Ａ４の作製）
　まず、下記表１に示す合金材Ａ１～Ａ４の名目組成で原料金属を混合し、合金材Ａ１～Ａ４を作製するための混合原料をそれぞれ用意した。次に、合金材Ａ１～Ａ４の混合原料それぞれについて、自動アーク溶解炉（大亜真空株式会社製）を使用し、アーク溶解法により、減圧Ａｒ雰囲気中で水冷銅ハース上に配置した混合原料を溶解することで溶湯を得て、溶湯を凝固させて合金塊（直径約３４ｍｍ、約５０ｇ）を作製した。さらに、合金塊の均質化のために、合金塊をそれぞれ反転させながら再溶解を６回繰り返すことで合金塊の合金材Ａ１～Ａ４を作製した（合金材作製工程）。 [Experiment 1]
(Production of alloy materials A1 to A4)
First, raw material metals were mixed with nominal compositions of alloy materials A1 to A4 shown in Table 1 below to prepare mixed raw materials for producing alloy materials A1 to A4, respectively. Next, for each of the mixed raw materials of the alloy materials A1 to A4, an automatic arc melting furnace (manufactured by Daia Vacuum Co., Ltd.) is used to arc melt the mixed raw materials placed on a water-cooled copper hearth in a reduced pressure Ar atmosphere. A molten metal was obtained by melting, and the molten metal was solidified to produce an alloy ingot (diameter of about 34 mm, about 50 g). Furthermore, in order to homogenize the alloy ingots, alloy materials A1 to A4 of the alloy ingots were produced by repeating remelting six times while inverting the alloy ingots (alloy material producing step).
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　上記表１に示すように、合金材Ａ１及びＡ２は、Ｂ（ボロン）を本発明に係る含有量の範囲内で含むＨＥＡ合金材（実施例）であり、合金材Ａ３は、Ｂを本発明に係る含有量の範囲外で含むＨＥＡ合金材（比較例）であり、合金材Ａ４は、Ｂを含まないＨＥＡ合金材（比較例）である。 As shown in Table 1 above, the alloy materials A1 and A2 are HEA alloy materials (examples) containing B (boron) within the content range according to the present invention, and the alloy material A3 contains B in accordance with the present invention. The alloy material A4 is an HEA alloy material (comparative example) containing the content outside the range of B, and the alloy material A4 is an HEA alloy material (comparative example) that does not contain B.
（合金加工物Ｗ１～Ｗ４の作製）
　続いて、合金材Ａ１～Ａ４それぞれに対して機械加工を施して合金加工体を成形体（１０ｍｍ×１０ｍｍ×４０ｍｍの直方体）として成形した（成形加工工程）。次に、合金材Ａ１～Ａ４から成形した合金加工体それぞれに対して擬溶体化熱処理を行った（擬溶体化熱処理工程）。擬溶体化熱処理では、大気雰囲気中で合金加工体を１１２０℃に１時間保持した後、急冷した。急冷方法としては、８００℃以上９００℃以下の平均冷却速度を約１０℃／ｓとする空冷を採用した。これにより、合金材Ａ１～Ａ４から合金加工物Ｗ１～Ｗ４をそれぞれ合金製造物として製造した。なお、擬溶体化熱処理工程は１０００℃～１１８０℃で０．１時間以上１００時間以下の範囲で、行うことができる。 (Production of alloy workpieces W1 to W4)
Subsequently, each of the alloy materials A1 to A4 was machined to form the alloy processed body into a compact (10 mm×10 mm×40 mm rectangular parallelepiped) (forming step). Next, quasi-solution heat treatment was performed on each of the alloy processed bodies formed from the alloy materials A1 to A4 (quasi-solution heat treatment step). In the quasi-solution heat treatment, the alloy work piece was held at 1120° C. for 1 hour in an air atmosphere and then quenched. As a quenching method, air cooling with an average cooling rate of about 10° C./s from 800° C. to 900° C. was adopted. As a result, alloy workpieces W1 to W4 were produced as alloy products from the alloy materials A1 to A4, respectively. The quasi-solution heat treatment step can be performed at 1000° C. to 1180° C. for 0.1 hour or more and 100 hours or less.
［実験２］
（合金粉末Ｐ１～Ｐ４の作製）
　まず、下記表２に示す合金粉末Ｐ１～Ｐ４の名目組成で原料金属を混合し、合金粉末Ｐ１～Ｐ４を作製するための混合原料をそれぞれ用意した。次に、合金粉末Ｐ１～Ｐ４の混合原料それぞれについて、高周波溶解炉を使用し、混合原料を溶解することで溶湯を得た（原料混合溶解工程）。次に、ガスアトマイズ法により、それぞれの溶湯を飛散、凝固させて合金材として合金粉末を得た（合金凝固工程）。 [Experiment 2]
(Preparation of alloy powders P1 to P4)
First, raw material metals were mixed with nominal compositions of alloy powders P1 to P4 shown in Table 2 below to prepare mixed raw materials for producing alloy powders P1 to P4, respectively. Next, for each of the mixed raw materials of the alloy powders P1 to P4, a high-frequency melting furnace was used to melt the mixed raw materials to obtain molten metal (raw material mixing and melting step). Next, by gas atomization, each molten metal was scattered and solidified to obtain an alloy powder as an alloy material (alloy solidification step).
　次に、得られた合金粉末それぞれをふるいにより分級することで粒径２０μｍ以上４５μｍ以下に選別し、合金粉末Ｐ１～Ｐ４を作製した（合金材作製工程）。レーザ回折式粒度分布測定装置を用いて、合金粉末Ｐ１～Ｐ４の粒度分布を測定したところ、それぞれの平均粒径は約３０μｍであった。 Next, each of the obtained alloy powders was classified by a sieve to select particles having a particle size of 20 μm or more and 45 μm or less, and alloy powders P1 to P4 were produced (alloy material production step). When the particle size distribution of the alloy powders P1 to P4 was measured using a laser diffraction particle size distribution analyzer, the average particle size of each was about 30 μm.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　上記表２に示すように、合金粉末Ｐ１は、Ｂを含まないＨＥＡ合金粉末（比較例）であり、基準試料として用意した。合金粉末Ｐ２は、Ｂを含むＨＥＡ合金粉末（実施例）であり、合金粉末Ｐ３は、Ｂ及びＴａを含むＨＥＡ合金粉末（実施例）である。合金粉末Ｐ４は、Ｂを含まずＴａを含むＨＥＡ合金粉末（比較例）である。なお、合金粉末Ｐ２の組成からＴｉの含有量を１０．７原子％に上げた試作粉末も作製したが、下記の積層造形の際に割れが生じる結果となった。この試作結果からＴｉの含有量の上限は１０原子％とした。 As shown in Table 2 above, the alloy powder P1 is a B-free HEA alloy powder (comparative example) and was prepared as a reference sample. The alloy powder P2 is an HEA alloy powder containing B (Example), and the alloy powder P3 is an HEA alloy powder containing B and Ta (Example). The alloy powder P4 is an HEA alloy powder (comparative example) that does not contain B but contains Ta. A trial powder with a higher Ti content of 10.7 atomic % was also produced from the composition of the alloy powder P2, but cracks occurred during the following layered manufacturing. Based on the results of this trial production, the upper limit of the Ti content was set to 10 atomic %.
（合金造形物Ｍ１～Ｍ５の作製）
　続いて、合金粉末Ｐ１～Ｐ４それぞれについて、積層造形装置（ＥＯＳ　ＧｍｂＨ製、型式：ＥＯＳＩＮＴ　Ｍ２８０）を使用し、ＳＬＭ法により、合金粉末から所望形状を有する積層造形体（高さ方向が積層方向である縦２５ｍｍ×横２５ｍｍ×高さ７０ｍｍの角柱材）を成形体として形成した。この際、ＳＬＭの条件は、合金粉末床の厚さｈを０．０４ｍｍとし、体積エネルギー密度Ｅが４０Ｊ／ｍｍ３以上１００Ｊ／ｍｍ３以下となるようにレーザ光の出力Ｐとレーザ光の走査速度Ｓとレーザ光の走査間隔Ｌとを制御した。 (Preparation of alloy moldings M1 to M5)
Subsequently, for each of the alloy powders P1 to P4, an additive manufacturing apparatus (manufactured by EOS GmbH, model: EOSINT M280) is used to form an additive manufacturing body having a desired shape from the alloy powder by the SLM method (the height direction is the stacking direction). A prismatic material measuring 25 mm long, 25 mm wide, and 70 mm high was formed as a compact. At this time, the conditions of the SLM are that the thickness h of the alloy powder bed is 0.04 mm, and the volume energy density E is 40 J/mm 3 or more and 100 J/mm 3 or less. The speed S and the scanning interval L of the laser beam were controlled.
　次に、合金粉末Ｐ１～Ｐ４から成形した積層造形体のそれぞれを合金粉末床から取り出した。その後、積層造形体それぞれに対して擬溶体化熱処理を行った（擬溶体化熱処理工程）。擬溶体化熱処理では、大気雰囲気中で積層造形体を１１２０℃で３時間保持した後、急冷した。急冷方法としては、８００℃以上９００℃以下の平均冷却速度を約１０℃／ｓとする空冷を採用した。これにより、合金粉末Ｐ１～Ｐ４からそれぞれ合金造形物Ｍ１～Ｍ４を合金製造物として製造した。なお、擬溶体化熱処理工程は１０００℃～１１８０℃で０．１時間以上１００時間以下の範囲で行うことができる。また、合金粉末Ｐ３から得た擬溶体化熱処理を施した合金造形物Ｍ３について、さらに大気雰囲気中で積層造形体を６５０℃で８時間保持した時効熱処理を施し、その後炉中で冷却した合金造形物Ｍ５を合わせて得た。 Next, each of the laminate-molded bodies molded from the alloy powders P1 to P4 was taken out from the alloy powder bed. After that, quasi-solution heat treatment was performed on each of the laminate-molded bodies (quasi-solution heat treatment step). In the quasi-solution heat treatment, the laminate-molded body was held at 1120° C. for 3 hours in an air atmosphere, and then rapidly cooled. As a quenching method, air cooling with an average cooling rate of about 10° C./s from 800° C. to 900° C. was adopted. As a result, alloy shaped objects M1 to M4 were produced as alloy products from the alloy powders P1 to P4, respectively. The quasi-solution heat treatment step can be performed at 1000° C. to 1180° C. for 0.1 hour or more and 100 hours or less. In addition, the alloy molded article M3 obtained from the alloy powder P3 and subjected to the quasi-solution heat treatment was further subjected to aging heat treatment by holding the layered molded article at 650 ° C. for 8 hours in an air atmosphere, and then cooled in a furnace. Product M5 was obtained in combination.
［実験３］
（合金加工物Ｗ１～Ｗ４及び合金造形物Ｍ１～Ｍ５の試験及び評価）
（機械的特性評価）
　合金加工物（合金製造物）Ｗ１～Ｗ４及び合金造形物（合金製造物）Ｍ１～Ｍ５のそれぞれについて、所定形状の試験体に加工した。この試験体の７００℃の高温環境下における機械的特性として引張強度及び破断伸びを測定し評価した。評価方法は、ＡＳＴＭ　Ｅ２１に準拠し、引張速度は耐力まで０．５％／ｍｉｎ、耐力以降破断までを５％／ｍｉｎとした。合金加工物Ｗ１～Ｗ４については、引張強度に関し、９００ＭＰａ以上の場合を「優秀」と評価し、８００ＭＰａ以上の場合を「合格」とし、８００ＭＰａ未満の場合を「不合格」とした。また、破断伸びに関しては、８％以上の場合を「優秀」と評価し、７％以上の場合を「合格」とし、７％未満の場合を「不合格」とした。合金造形物Ｍ１～Ｍ５については、合金加工物よりも凝固組織が微細となるためより高い特性が見込まれる。そのため、引張強度に関しては、１０００ＭＰａ以上の場合を「合格」と評価し、それ未満の場合を「不合格」とした。また、破断伸びに関しては、１０％以上の場合を「合格」とし、それ未満の場合を「不合格」とした。これらの結果を表３に示す。 [Experiment 3]
(Test and Evaluation of Alloy Workpieces W1 to W4 and Alloy Models M1 to M5)
(Mechanical property evaluation)
The alloy processed products (alloy manufactured products) W1 to W4 and the alloy shaped products (alloy manufactured products) M1 to M5 were processed into specimens of predetermined shapes. Tensile strength and elongation at break were measured and evaluated as mechanical properties of this specimen in a high temperature environment of 700°C. The evaluation method was based on ASTM E21, and the tensile speed was set to 0.5%/min up to yield strength and 5%/min from yield strength to breakage. Regarding the alloy workpieces W1 to W4, the tensile strength of 900 MPa or more was evaluated as "excellent", the case of 800 MPa or more was evaluated as "acceptable", and the case of less than 800 MPa was evaluated as "failed". In addition, regarding the elongation at break, the case of 8% or more was evaluated as "excellent", the case of 7% or more was evaluated as "acceptable", and the case of less than 7% was evaluated as "failed". The alloy shaped products M1 to M5 are expected to have higher properties because the solidified structure is finer than that of the alloy processed product. Therefore, regarding the tensile strength, a case of 1000 MPa or more was evaluated as "acceptable", and a case of less than that was evaluated as "failed". In addition, regarding the elongation at break, a case of 10% or more was defined as "accepted", and a case of less than that was defined as "failed". These results are shown in Table 3.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　また、合金造形物（合金製造物）Ｍ１～Ｍ５の所定形状の試験体について、常温～８５０℃までの各環境温度での機械的特性（引張強度及び破断伸び）を測定し評価した。評価方法は、上記と同様とした。結果を表４に示す。 In addition, the mechanical properties (tensile strength and elongation at break) were measured and evaluated at each environmental temperature from room temperature to 850°C for the alloy shaped objects (alloy products) M1 to M5 of predetermined shapes. The evaluation method was the same as above. Table 4 shows the results.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　上記表３に示すように、Ｂを本発明に係る含有量の範囲で含む合金加工物Ｗ１及びＷ２は、Ｂを含まない合金加工物Ｗ４と比較して高温環境下における機械的特性が向上したことがわかる。さらに、Ｂを本発明に係る含有量の範囲外（０．１５原子％以上）で含む合金加工物Ｗ３は、合金加工物Ｗ１及びＷ２よりも破断伸びが低下した。また、Ｂを含む合金造形物Ｍ２及びＭ３（実施例）は、Ｂを含まない合金造形物Ｍ１（比較例）と比べ高温環境下における機械的特性が向上したことがわかる。 As shown in Table 3 above, the alloy workpieces W1 and W2 containing B within the content range according to the present invention have improved mechanical properties in a high-temperature environment compared to the alloy workpiece W4 that does not contain B. I understand. Furthermore, the alloy workpiece W3 containing B outside the range of the content according to the present invention (0.15 atomic % or more) had a fracture elongation lower than those of the alloy workpieces W1 and W2. In addition, it can be seen that the alloy shaped products M2 and M3 (examples) containing B have improved mechanical properties in a high-temperature environment compared to the alloy shaped product M1 (comparative example) that does not contain B.
　上記表４に示すように、合金造形物Ｍ１では、環境温度が７００℃以上となると試験体の機械的特性が顕著に低下した。また、合金造形物Ｍ４では、合金造形物Ｍ１よりも延性は優れていたが、同様に環境温度が７００℃となると機械的特性が低下した。一方、合金造形物Ｍ２及びＭ３では、試験体の機械的特性は、低下する傾向が見られるものの、７００℃を超えても維持が可能であることが確認された。そして、Ｍ２及びＭ３では、７００℃における破断伸びは実用に供される程度の数値が得られている。さらに、ＢとＴａを同時に含有するＭ３では、８５０℃のより高温でも破断伸びの低下が抑制されることが分かった。Ｍ３に時効熱処理を施したＭ５はＭ３と同等の優れた高温での機械特性を保持しつつ、低温部の強度向上の効果が見られた。 As shown in Table 4 above, in the alloy model M1, the mechanical properties of the specimen significantly decreased when the environmental temperature reached 700°C or higher. Also, the alloy shaped article M4 was superior in ductility to the alloy shaped article M1, but similarly, when the environmental temperature reached 700° C., the mechanical properties decreased. On the other hand, in the alloy molded products M2 and M3, it was confirmed that the mechanical properties of the specimens tended to deteriorate, but could be maintained even at temperatures exceeding 700°C. Further, in M2 and M3, values of breaking elongation at 700° C. that are practically available are obtained. Furthermore, it was found that M3, which contains both B and Ta, suppresses a decrease in elongation at break even at a higher temperature of 850°C. M5, which was obtained by subjecting M3 to aging heat treatment, showed the effect of improving the strength of the low-temperature portion while maintaining excellent mechanical properties at high temperatures equivalent to those of M3.
（微細組織観察１）
　まず、合金加工物Ｗ１～Ｗ４及び合金造形物Ｍ１～Ｍ５のそれぞれに対して、Ｘ線回折（ＸＲＤ）測定を行い、母相結晶粒の結晶構造及び析出相の同定を行った。その結果、合金加工物Ｗ１～Ｗ４及び合金造形物Ｍ１～Ｍ５の全てにおいて、母相結晶粒の結晶構造は主に面心立方晶（ＦＣＣ）からなると判断された。ただし、Ｘ線回折測定では、面心立方晶（ＦＣＣ）と単純立方晶（ＳＣ）とを完全に区別することは困難なため、単純立方晶を含まないとは断定できない。 (Microstructure observation 1)
First, the alloy processed products W1 to W4 and the alloy shaped products M1 to M5 were each subjected to X-ray diffraction (XRD) measurement to identify the crystal structure of the parent phase crystal grains and the precipitated phases. As a result, it was determined that the crystal structure of the parent phase crystal grains was mainly face-centered cubic (FCC) in all of the alloy workpieces W1 to W4 and the alloy shaped products M1 to M5. However, since it is difficult to completely distinguish between face-centered cubic (FCC) and simple cubic (SC) crystals by X-ray diffraction measurement, it cannot be concluded that simple cubic crystals are not included.
　次に、合金加工物Ｗ１～Ｗ４及び合金造形物Ｍ１～Ｍ５のそれぞれについて、切断して切断片の断面を鏡面研磨し、当該断面に対して１０質量％のシュウ酸水溶液を使用し、３Ｖ×０．２Ａの電界条件で電解エッチング処理を行った。その上で、それぞれの切断片の処理断面に対してＳＥＭ観察を行った。析出物は合金製造物に応力が作用した場合に割れの起点となり、析出物のサイズが大きいほど割れの起点となりやすい傾向にある。そこで、処理断面を４００μｍ×３００μｍの範囲で観察した場合において、この観察範囲にサイズが１０μｍ以上の析出物が観察されなかった場合を「優秀」と評価し、サイズが５０μｍ以上の粗大な析出物が観察されなかった場合を「合格」とし、サイズが５０μｍ以上の粗大な析出物が観察された場合を「不合格」とした。これらの結果を表５に示す。さらに、図２Ａは、合金加工物Ｗ１の処理断面のＳＥＭ観察により得られる二次電子像である。図２Ｂは、合金加工物Ｗ３の処理断面のＳＥＭ観察により得られる二次電子像である。 Next, each of the alloy workpieces W1 to W4 and the alloy shaped objects M1 to M5 is cut, the cross section of the cut piece is mirror-polished, and the cross section is treated with a 10% by mass oxalic acid aqueous solution, 3V× An electrolytic etching treatment was performed under an electric field condition of 0.2A. Then, SEM observation was performed on the processed cross section of each cut piece. Precipitates become starting points of cracks when stress acts on the alloy product, and the larger the size of the precipitates, the more likely they are to become starting points of cracks. Therefore, when the treated cross section was observed in the range of 400 μm × 300 μm, the case where no precipitates with a size of 10 μm or more were observed in this observation range was evaluated as “excellent”, and coarse precipitates with a size of 50 μm or more were evaluated. A case where no was observed was evaluated as "acceptable", and a case where a coarse precipitate having a size of 50 µm or more was observed was evaluated as "disabled". These results are shown in Table 5. Furthermore, FIG. 2A is a secondary electron image obtained by SEM observation of the treated cross section of the alloy workpiece W1. FIG. 2B is a secondary electron image obtained by SEM observation of the treated cross section of the alloy workpiece W3.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　表５に示すように、合金加工物Ｗ１及びＷ２の切断片には粗大な析出物が観察されなかった。特に、図２Ａに示すように、合金加工物Ｗ１の切断片の析出物は４００μｍ×３００μｍの処理断面領域あたり１個以下であり、ほとんど観察されなかった。一方、表５及図２Ｂに示すように、合金加工物Ｗ３の切断片には、サイズが５０μｍ以上の粗大な析出物が観察された。このような粗大な析出物が観察される場合には、室温環境下における機械的特性が低下するおそれがある。なお、このような粗大な析出物が生成する組成の合金材を積層造形プロセスに適用しようとすると造形時に粗大な析出物に起因する割れが発生し易いので、積層造形プロセスには不向きである。また、合金加工物Ｗ４と合金造形物Ｍ１及びＭ４は、析出物は生成されないが高温での機械的特性に劣る。 As shown in Table 5, no coarse precipitates were observed in the cut pieces of alloy workpieces W1 and W2. In particular, as shown in FIG. 2A, the number of precipitates in the cut piece of the alloy workpiece W1 was 1 or less per processed cross-sectional area of 400 μm×300 μm, and was hardly observed. On the other hand, as shown in Table 5 and FIG. 2B, coarse precipitates with a size of 50 μm or more were observed in the cut piece of the alloy workpiece W3. When such coarse precipitates are observed, there is a possibility that the mechanical properties under the room temperature environment may deteriorate. If an alloy material with a composition that produces such coarse precipitates is applied to the additive manufacturing process, cracks are likely to occur due to the coarse precipitates during modeling, so it is not suitable for the additive manufacturing process. Also, the alloy workpiece W4 and the alloy shaped articles M1 and M4 do not form precipitates, but have poor mechanical properties at high temperatures.
（微細組織観察２）
　合金造形物Ｍ２について、母相結晶粒中の極小粒子を評価するために、ＳＴＥＭ（Scanning Transmission Electron Microscope）による高倍率観察を行った。 (Microstructure observation 2)
High-magnification observation by STEM (Scanning Transmission Electron Microscope) was performed in order to evaluate extremely small particles in the mother phase crystal grains of the alloy model M2.
　まず、上記で得た合金造形物Ｍ２の切断片の一面を鏡面研磨し、ＦＩＢ（Focused Ion Beam）によるマイクロサンプリング法により、研磨面から１００ｎｍ程度の厚さの試験片を切り出した。この際、マイクロサンプリング法には株式会社日立ハイテク社製ＦＢ－２１００型を使用した。次に、この試験片について、ＳＴＥＭによる観察を行った。ＳＴＥＭの観察条件は、以下の通りとした。 First, one surface of the cut piece of the alloy model M2 obtained above was mirror-polished, and a test piece with a thickness of about 100 nm was cut from the polished surface by a microsampling method using FIB (Focused Ion Beam). At this time, FB-2100 model manufactured by Hitachi High-Tech Co., Ltd. was used for the microsampling method. Next, this test piece was observed by STEM. Observation conditions of STEM were as follows.
＜ＳＴＥＭ観察の条件＞
　試料の厚さ：１００ｎｍ
　装置の機種：日本電子株式会社製　型式ＪＥＭ－ＡＲＭ２００Ｆ
　加速電圧：２００ｋＶ <Conditions for STEM observation>
Sample thickness: 100 nm
Device model: Model JEM-ARM200F manufactured by JEOL Ltd.
Accelerating voltage: 200 kV
　図３Ａは、合金造形物Ｍ２のＳＴＥＭ観察により得られる母相結晶粒の電子回折パターンであり、図３Ｂは、合金造形物Ｍ２のＳＴＥＭ観察により得られる母相結晶粒の暗視野像（ＤＦ－ＳＴＥＭ）である。また、図４は、エネルギー分散型Ｘ線分光法（ＥＤＸ：Energy Dispersive X-ray Spectroscopy）により合金造形物Ｍ２の母相結晶粒中の極小粒子の元素マッピングを行った結果を示す画像である。 FIG. 3A is an electron diffraction pattern of the matrix phase crystal grains obtained by STEM observation of the alloy shaped article M2, and FIG. 3B is a dark field image (DF- STEM). Further, FIG. 4 is an image showing the results of elemental mapping of extremely small particles in the matrix crystal grains of the alloy shaped product M2 by energy dispersive X-ray spectroscopy (EDX).
　図３Ａの電子回折パターンから、面心立方晶（ＦＣＣ）相に由来するパターンとγ‘相に由来するパターンとを確認できる。図３Ｂの暗視野像から、最大径（最大長さ）のばらつきはほとんどなく５０～６０ｎｍ程度であり、平均粒径が約５４ｎｍの極小粒子が分散していることを確認できる。なお、観察像において５つの極小粒子の最大径を測定し、その平均値を平均粒径とした。さらに、図４に示す元素マッピングを行った結果から、母相結晶粒中において極小粒子には他の部分よりＮｉ及びＴｉが濃化していることを確認できる。このような極小粒子は、電子回折パターンで観察されたγ’相であると考えられる。γ’相は、結晶粒中における転位の進展に対する抵抗となるために機械特性の改善に寄与する。なお、合金造形物Ｍ３並びにＭ５においても、ＳＴＥＭによる高倍率観察を行ったところ、同様のＦＣＣ相から成る母相結晶粒とＮｉ及びＴｉが濃化した極小粒子からなる微細組織が確認された。 From the electron diffraction pattern in FIG. 3A, a pattern derived from the face-centered cubic (FCC) phase and a pattern derived from the γ' phase can be confirmed. From the dark-field image of FIG. 3B, it can be confirmed that the maximum diameter (maximum length) is about 50 to 60 nm with almost no variation, and that extremely small particles with an average diameter of about 54 nm are dispersed. In addition, the maximum diameters of five extremely small particles were measured in the observation image, and the average value was taken as the average particle diameter. Furthermore, from the results of the elemental mapping shown in FIG. 4, it can be confirmed that Ni and Ti are more concentrated in the very small grains than in the other portions of the matrix crystal grains. Such very small particles are believed to be the γ' phase observed in the electron diffraction pattern. The γ' phase contributes to the improvement of mechanical properties by providing resistance to dislocation propagation in grains. Also in the alloy shaped products M3 and M5, high-magnification observation by STEM confirmed a similar microstructure composed of matrix crystal grains composed of the FCC phase and extremely small grains in which Ni and Ti were concentrated.
（微細組織観察３）
　合金造形物Ｍ１～Ｍ５について、母相結晶粒界におけるＢの分布を評価するために、ＳＩＭＳ（Secondary Ion Mass Spectroscopy）による元素分布の定性評価を行った。 (Microstructure observation 3)
In order to evaluate the distribution of B in the grain boundaries of the parent phase, the alloy shaped products M1 to M5 were subjected to qualitative evaluation of the elemental distribution by SIMS (Secondary Ion Mass Spectroscopy).
　まず、上記で得た合金造形物Ｍ１～Ｍ５の切断片の一面を鏡面研磨し、ＳＩＭＳによる観察を行った。ＳＩＭＳの観察条件は、以下の通りとした。 First, one surface of the cut pieces of the alloy shaped objects M1 to M5 obtained above was mirror-polished and observed by SIMS. The SIMS observation conditions were as follows.
＜ＳＩＭＳ観察の条件＞
　装置の機種：ＡＭＥＴＥＫ　ＣＡＭＥＣＡ社製二次イオン質量分析器　型式IMS－7F
　一次イオン条件：Ｃｓ＋、１５ｋＶ
　分析領域：１００μｍ×１００μｍ
　二次イオン極性：負
　検出元素：Ｂ（ＢＯ２ －イオンとして検出） <Conditions for SIMS observation>
Apparatus model: AMETEK CAMECA secondary ion mass spectrometer model IMS-7F
Primary ion conditions: Cs + , 15 kV
Analysis area: 100 μm×100 μm
Secondary ion polarity: negative Detected element: B (detected as BO 2 - ion)
　図５は、合金造形物Ｍ１～Ｍ５のＳＩＭＳ観察により得られたＢＯ２ －イオン強度分布を示す画像であり、図６は、図５の各図における矢印に沿う各位置のＢＯ２ －イオン強度分布を示すグラフである。イオン強度の絶対値は装置の測定条件などに依存するため、本検討では上記ＳＩＭＳ観察の条件のように測定条件を定めて各試料を観察し、その際に取得したイオン強度比にて相対的に定性評価を実施した。 FIG . 5 is an image showing the BO 2 - ion intensity distribution obtained by SIMS observation of the alloy shaped objects M1 to M5, and FIG. It is a graph which shows distribution. Since the absolute value of the ion intensity depends on the measurement conditions of the device, etc., in this study, each sample was observed under the same measurement conditions as the above SIMS observation conditions, and the ion intensity ratio obtained at that time was used as a relative value. A qualitative evaluation was performed on
　図５及び図６からは、Ｍ２、Ｍ３、及びＭ５においては、対応する原料粉末（Ｐ２及びＰ３）に含まれるＢが造形体に含まれ、Ｂを含まない原料粉末（Ｐ１及びＰ４）より得たＭ１及びＭ４よりも全体として１０倍以上の高濃度にてＢが存在することが確認された。また、ＢとＴａを含む粉末（Ｐ３）より得たＭ３及びＭ５では結晶粒界へのＢの偏在が見られた。Ｂを含まずＴａのみを含む粉末（Ｐ４）でも粒界へのＢの偏在が生じたが、そのイオン強度比は低く偏在量は少なかったと見られる。なお、Ｂを含まない原料粉末（Ｐ１及びＰ４）は、Ｂの相対二次イオン強度が少なくなっている。これは、Ｂを含まない原料粉末（Ｐ１及びＰ４）が、名目組成ではＢを含まないものの、実際にはＢを不純物としてppmオーダーで含んでいることに対応することである。Ｂを含まない粉末（Ｐ４）でもＢの偏在が生じているのは、粉末（Ｐ４）は、名目組成ではＢを含まないものの、実際にはＢを不純物としてppmオーダーで含んでいるためである。以上のように、先に示した表３で７００℃において優れた機械的性質を示したＭ２、Ｍ３、及びＭ５が、その他のＭ１及びＭ４に比して特に結晶粒界に高い濃度のＢが存在することが確認された。この粒界に存在するＢは高温での変形様式である粒界滑りに対する抵抗として作用するため、高温機械特性が改善されたと考えられる。 5 and 6, in M2, M3, and M5, B contained in the corresponding raw material powders (P2 and P3) is contained in the shaped bodies, and B is obtained from the raw material powders (P1 and P4) that do not contain B. It was confirmed that B was present at a concentration 10 times higher as a whole than M1 and M4. In M3 and M5 obtained from the powder (P3) containing B and Ta, uneven distribution of B at grain boundaries was observed. Even in the powder (P4) containing only Ta and not containing B, uneven distribution of B occurred at the grain boundary, but the ionic strength ratio was low and the amount of uneven distribution was small. The raw material powders (P1 and P4) containing no B have a low relative secondary ion intensity of B. This corresponds to the fact that the B-free raw material powders (P1 and P4) do not contain B in their nominal composition, but actually contain B as an impurity on the order of ppm. The reason why B is unevenly distributed even in the powder (P4) that does not contain B is that the powder (P4) does not contain B in its nominal composition, but actually contains B as an impurity in ppm order. . As described above, M2, M3, and M5, which showed excellent mechanical properties at 700° C. in Table 3 above, have a particularly high concentration of B at the grain boundaries compared to the other M1 and M4. confirmed to exist. It is considered that the high-temperature mechanical properties are improved because the B present at the grain boundaries acts as a resistance against grain boundary sliding, which is a mode of deformation at high temperatures.
　上記の実施形態や実験例は、本発明の理解を助けるために説明したものであり、本発明は、記載した具体的な構成のみに限定されるものではない。例えば、実施形態の構成の一部を当業者の技術常識の構成に置き換えることが可能であり、また、実施形態の構成に当業者の技術常識の構成を加えることも可能である。すなわち、本発明は、本明細書の実施形態や実験例の構成の一部について、発明の技術的思想を逸脱しない範囲で、削除・他の構成に置換・他の構成の追加をすることが可能である。
　本明細書で引用した全ての刊行物、特許及び特許出願はそのまま引用により本明細書に組み入れられるものとする。 The above-described embodiments and experimental examples are described to aid understanding of the present invention, and the present invention is not limited only to the specific configurations described. For example, it is possible to replace part of the configuration of the embodiment with a configuration of common technical knowledge of a person skilled in the art, and it is also possible to add a configuration of common general technical knowledge of a person skilled in the art to the configuration of the embodiment. That is, in the present invention, part of the configurations of the embodiments and experimental examples of the present specification can be deleted, replaced with other configurations, or added with other configurations without departing from the technical idea of the invention. It is possible.
All publications, patents and patent applications cited herein are hereby incorporated by reference in their entirety.

Claims (7)

  1. 　Ｃｏ、Ｃｒ、Ｆｅ、及びＮｉをそれぞれ５原子％以上４０原子％以下の範囲で含み、Ｍｏを０原子％超８原子％以下の範囲で含み、Ｔｉを１原子％以上１０原子％以下の範囲で含み、Ｂを０原子％超０．１５原子％未満の範囲で含み、Ｔａ及びＮｂの少なくとも一種を４原子％以下で含むか又は含まず、残部が不可避的不純物からなることを特徴とする合金材。 Contains Co, Cr, Fe, and Ni in the range of 5 atomic % to 40 atomic %, Mo in the range of more than 0 atomic % to 8 atomic %, and Ti in the range of 1 atomic % to 10 atomic % and contains B in the range of more than 0 atomic% and less than 0.15 atomic%, contains or does not contain at least one of Ta and Nb at 4 atomic% or less, and the balance consists of unavoidable impurities alloy material.
  2. 　前記Ｂを０．０３原子％以上０．１２原子％以下の範囲で含むことを特徴とする請求項１に記載の合金材。 The alloy material according to claim 1, characterized in that said B is contained in the range of 0.03 atomic % or more and 0.12 atomic % or less.
  3. 　Ｔａ及びＮｂの少なくとも一種を４原子％以下で含むことを特徴とする請求項１又は２に記載の合金材。 The alloy material according to claim 1 or 2, characterized by containing at least one of Ta and Nb at 4 atomic % or less.
  4. 　前記Ｔｉと、前記Ｔａ及びＮｂの少なくとも一種との合計が３原子％以上１０原子％以下であることを特徴とする請求項３に記載の合金材。 The alloy material according to claim 3, wherein the total content of the Ti and at least one of Ta and Nb is 3 atomic % or more and 10 atomic % or less.
  5. 　前記Ｃｏを２５原子％以上３８原子％以下の範囲で含み、前記Ｃｒを１６原子％以上２３原子％以下の範囲で含み、前記Ｆｅを１２原子％以上２０原子％以下の範囲で含み、前記Ｎｉを１７原子％以上２８原子％以下の範囲で含み、前記Ｍｏを１原子％以上７原子％以下の範囲で含み、前記Ｔｉを２原子％以上９原子％以下の範囲で含むことを特徴とする請求項１～４のいずれか１項に記載の合金材。 The Co is contained in the range of 25 atomic % or more and 38 atomic % or less, the Cr is contained in the range of 16 atomic % or more and 23 atomic % or less, the Fe is contained in the range of 12 atomic % or more and 20 atomic % or less, and the Ni in the range of 17 atomic % or more and 28 atomic % or less, the Mo in the range of 1 atomic % or more and 7 atomic % or less, and the Ti in the range of 2 atomic % or more and 9 atomic % or less. The alloy material according to any one of claims 1 to 4.
  6. 　請求項１～５のいずれか１項に記載の合金材を用いた合金製造物であって、
    　前記合金製造物の母相結晶粒中に平均粒径１３０ｎｍ以下の極小粒子が分散析出していることを特徴とする合金製造物。     An alloy product using the alloy material according to any one of claims 1 to 5,
    An alloy product characterized in that extremely small particles having an average grain size of 130 nm or less are dispersed and precipitated in the parent phase crystal grains of the alloy product.
  7. 　請求項６に記載の合金製造物を備える機械装置。 A mechanical device comprising the alloy product according to claim 6.
PCT/JP2022/022984 2021-06-08 2022-06-07 Alloy material, alloy product using alloy material, and machine device provided with alloy product WO2022260044A1 (en)

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WO2019088157A1 (en) 2017-10-31 2019-05-09 日立金属株式会社 Alloy material, product using said alloy material, and fluid machine having said product
JP2019534374A (en) * 2017-09-08 2019-11-28 ポステック アカデミー−インダストリー ファンデーション Boron-doped high entropy alloy and method for producing the same
CN112792346A (en) * 2020-12-29 2021-05-14 南通金源智能技术有限公司 Preparation method of TiB 2-enhanced high-entropy alloy powder for 3D printing
JP2021096053A (en) 2019-12-18 2021-06-24 達登志 緑川 Ashes burial method and ash container

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JP2019534374A (en) * 2017-09-08 2019-11-28 ポステック アカデミー−インダストリー ファンデーション Boron-doped high entropy alloy and method for producing the same
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JP2021096053A (en) 2019-12-18 2021-06-24 達登志 緑川 Ashes burial method and ash container
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